sequence_id
stringlengths
7
7
sequence_name
stringlengths
4
573
sequence
listlengths
1
348
keywords
listlengths
1
8
score
int64
1
2.35k
offset_a
int64
-14,827
666,262,453B
offset_b
int64
0
635M
cross_references
listlengths
1
128
former_ids
listlengths
1
3
author
stringlengths
7
231
timestamp
timestamp[us]date
1999-12-11 03:00:00
2025-07-19 00:40:46
filename
stringlengths
29
29
hash
stringlengths
32
32
A380815
a(n) = A379343(A378684(n)).
[ "1", "5", "2", "4", "3", "6", "12", "9", "14", "7", "11", "10", "13", "8", "15", "23", "20", "25", "18", "27", "16", "22", "21", "24", "19", "26", "17", "28", "38", "35", "40", "33", "42", "31", "44", "29", "37", "36", "39", "34", "41", "32", "43", "30", "45", "57", "54", "59", "52", "61", "50", "63", "48", "65", "46", "56", "55", "58", "53", "60", "51", "62", "49", "64", "47", "66" ]
[ "nonn", "tabf" ]
28
1
2
[ "A000027", "A000384", "A016813", "A376214", "A378684", "A379342", "A379343", "A380200", "A380245", "A380815", "A380817", "A381662", "A381663", "A381664" ]
null
Boris Putievskiy, Feb 04 2025
2025-06-24T09:29:19
oeisdata/seq/A380/A380815.seq
2e59e03c59b04fa7cad409f0e20912e2
A380816
Number of pairs (x, y) with 0 < x < y < n such that x^y = y^x modulo n.
[ "0", "0", "0", "0", "1", "1", "5", "2", "2", "3", "5", "6", "8", "8", "6", "18", "11", "7", "20", "16", "15", "17", "28", "28", "15", "23", "32", "27", "24", "22", "35", "88", "20", "31", "19", "34", "32", "43", "35", "72", "33", "40", "37", "52", "45", "51", "57", "134", "36", "37", "38", "73", "65", "73", "61", "118", "72", "52", "59", "94", "61", "74", "111", "428", "67", "65", "69" ]
[ "nonn", "nice" ]
25
1
7
null
null
Peter Schorn, Feb 04 2025
2025-03-17T11:31:01
oeisdata/seq/A380/A380816.seq
3f21a2846b9843f74352fc4b946204f0
A380817
a(n) = A379343(A380245(n)).
[ "1", "2", "3", "4", "5", "6", "9", "10", "7", "8", "11", "12", "13", "14", "15", "20", "21", "18", "19", "16", "17", "22", "23", "24", "25", "26", "27", "28", "35", "36", "33", "34", "31", "32", "29", "30", "37", "38", "39", "40", "41", "42", "43", "44", "45", "54", "55", "52", "53", "50", "51", "48", "49", "46", "47", "56", "57", "58", "59", "60", "61", "62", "63", "64", "65", "66" ]
[ "nonn", "tabf" ]
45
1
2
[ "A000027", "A000384", "A016813", "A056023", "A376214", "A378684", "A378762", "A379342", "A379343", "A380200", "A380245", "A380815", "A380817", "A381662", "A381663", "A381664", "A381968", "A382499", "A382679", "A382680", "A383419", "A383589", "A383590", "A383722", "A383723", "A383724" ]
null
Boris Putievskiy, Feb 04 2025
2025-06-24T09:58:37
oeisdata/seq/A380/A380817.seq
77d166e77bb7fa67d275e7fcf85743b9
A380818
Numbers k such that the Diophantine equation d_r*x^r + ... + d_0*x^0 = 0 has an integer solution. k = (d_r .. d_0) in decimal notation, d_i are the digits of k.
[ "0", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "22", "24", "26", "28", "30", "33", "36", "39", "40", "44", "48", "50", "55", "60", "66", "70", "77", "80", "88", "90", "99", "100", "110", "120", "121", "130", "132", "140", "143", "144", "150", "154", "156", "160", "165", "168", "169", "170", "176", "180", "187", "190", "198", "200", "210", "220", "230", "231", "240", "242", "250" ]
[ "nonn", "base" ]
11
1
2
[ "A037124", "A380818" ]
null
Ctibor O. Zizka, Feb 04 2025
2025-02-05T22:09:03
oeisdata/seq/A380/A380818.seq
684f0bdaedaa15f2cced21584a2934ce
A380819
Triangle read by rows where row n lists "weak" divisors d | n (i.e., d in A052485) such that rad(d)^2 does not divide d, where rad = A007947.
[ "2", "3", "2", "5", "2", "3", "6", "7", "2", "3", "2", "5", "10", "11", "2", "3", "6", "12", "13", "2", "7", "14", "3", "5", "15", "2", "17", "2", "3", "6", "18", "19", "2", "5", "10", "20", "3", "7", "21", "2", "11", "22", "23", "2", "3", "6", "12", "24", "5", "2", "13", "26", "3", "2", "7", "14", "28", "29", "2", "3", "5", "6", "10", "15", "30", "31", "2", "3", "11", "33", "2", "17", "34", "5", "7", "35", "2", "3", "6", "12", "18" ]
[ "nonn", "tabf", "easy" ]
7
2
1
[ "A000005", "A001694", "A005361", "A007947", "A027750", "A052485", "A183093", "A379545", "A380672", "A380819" ]
null
Michael De Vlieger, Feb 13 2025
2025-02-16T23:02:26
oeisdata/seq/A380/A380819.seq
f9d71a5a0bbf1d2c52dc34d28b0d327c
A380820
a(0) = 0, a(1) = 1, and for n >= 2, a(n) = a(n-1) + a(n-2) if a(n-1) < n, otherwise a(n-1) - n.
[ "0", "1", "1", "2", "3", "5", "8", "1", "9", "0", "9", "9", "18", "5", "23", "8", "31", "14", "45", "26", "6", "32", "10", "42", "18", "60", "34", "7", "41", "12", "53", "22", "75", "42", "8", "50", "14", "64", "26", "90", "50", "9", "59", "16", "75", "30", "105", "58", "10", "68", "18", "86", "34", "120", "66", "11", "77", "20", "97", "38", "135", "74", "12", "86", "22", "108", "42", "150" ]
[ "nonn", "easy" ]
19
0
4
[ "A000027", "A000045", "A005843", "A008597", "A016825", "A017089", "A017221", "A017497", "A322558", "A380820" ]
null
Ya-Ping Lu, Feb 04 2025
2025-02-14T23:11:09
oeisdata/seq/A380/A380820.seq
dca51d72e76aba29b55e6a1b485124b0
A380821
Length of the shorts leg in the unique primitive Pythagorean triple whose inradius is A000032(n) and such that its long leg and its hypotenuse are consecutive natural numbers.
[ "5", "3", "7", "9", "15", "23", "37", "59", "95", "153", "247", "399", "645", "1043", "1687", "2729", "4415", "7143", "11557", "18699", "30255", "48953", "79207", "128159", "207365", "335523", "542887", "878409", "1421295", "2299703", "3720997", "6020699", "9741695", "15762393", "25504087", "41266479", "66770565", "108037043" ]
[ "nonn", "easy", "changed" ]
20
0
1
[ "A000032", "A380821", "A380823", "A380824", "A386201" ]
null
Miguel-Ángel Pérez García-Ortega, Feb 04 2025
2025-07-14T22:52:17
oeisdata/seq/A380/A380821.seq
88a00b19798370946edbcd508ccc973c
A380822
Triangle read by rows: T(n,k) is the number of compositions of n with k pairs of equal adjacent parts and all parts in standard order.
[ "1", "0", "1", "1", "0", "1", "1", "1", "0", "1", "0", "3", "1", "0", "1", "2", "1", "4", "1", "0", "1", "3", "3", "3", "5", "1", "0", "1", "2", "10", "5", "4", "6", "1", "0", "1", "5", "9", "17", "8", "5", "7", "1", "0", "1", "8", "16", "22", "26", "10", "6", "8", "1", "0", "1", "10", "35", "33", "37", "37", "12", "7", "9", "1", "0", "1", "19", "44", "80", "59", "56", "48", "14", "8", "10", "1", "0", "1" ]
[ "nonn", "easy", "tabl" ]
17
1
12
[ "A000110", "A003242", "A047998", "A106356", "A107429", "A126347", "A278984", "A380822", "A383253" ]
null
John Tyler Rascoe, May 08 2025
2025-05-08T16:57:04
oeisdata/seq/A380/A380822.seq
2d5123e785db84af0634ccd32e4b217f
A380823
Semiperimeter of the unique primitive Pythagorean triple whose inradius is A000032(n) and such that its long leg and its hypotenuse are consecutive natural numbers.
[ "15", "6", "28", "45", "120", "276", "703", "1770", "4560", "11781", "30628", "79800", "208335", "544446", "1423828", "3725085", "9748320", "25514796", "66787903", "174835650", "457697640", "1198222581", "3136914028", "8212428720", "21500225295", "56288009526", "147363418828", "385801624845", "1010040449160", "2644318093956", "6922911197503" ]
[ "nonn", "easy" ]
29
0
1
[ "A000032", "A380821", "A380823", "A380824", "A381721" ]
null
Miguel-Ángel Pérez García-Ortega, Feb 04 2025
2025-03-21T02:24:05
oeisdata/seq/A380/A380823.seq
6da485e0c4089ec8a64319ca60639d84
A380824
Area of the unique primitive Pythagorean triple whose inradius is A000032(n) and such that its long leg and its hypotenuse are consecutive natural numbers.
[ "30", "6", "84", "180", "840", "3036", "12654", "51330", "214320", "895356", "3767244", "15880200", "67083870", "283656366", "1200287004", "5081015940", "21514542240", "91113336516", "385900503534", "1634538491850", "6923592200280", "29327695892556", "124231206250884", "526244219948880", "2229186359036190", "9442932766091286" ]
[ "nonn", "easy" ]
20
0
1
[ "A000032", "A380821", "A380823", "A380824", "A381721" ]
null
Miguel-Ángel Pérez García-Ortega, Feb 04 2025
2025-03-14T21:30:53
oeisdata/seq/A380/A380824.seq
1b6ae5b4328b54fea5ca3159c426c93b
A380825
Indices of triangular numbers that are the products of triangular numbers larger than 1.
[ "8", "9", "20", "24", "27", "35", "39", "44", "54", "55", "75", "80", "84", "90", "98", "99", "104", "132", "135", "153", "175", "189", "195", "207", "224", "230", "231", "252", "260", "272", "275", "279", "285", "296", "324", "350", "351", "374", "399", "405", "440", "455", "459", "475", "494", "539", "560", "567", "575", "594", "615", "620", "624", "665", "675" ]
[ "nonn" ]
15
1
1
[ "A000217", "A003056", "A068143", "A380825" ]
null
Kelvin Voskuijl, Feb 04 2025
2025-02-13T12:20:58
oeisdata/seq/A380/A380825.seq
d0b6ac1c3bd660a7dd68a0631bcd12a3
A380826
Expansion of e.g.f. (1/x) * Series_Reversion( x * exp(-3*x) / (1 + x*exp(-2*x)) ).
[ "1", "4", "43", "810", "22273", "811728", "36979467", "2025462736", "129748802401", "9522843081984", "788169731306059", "72641846664240384", "7379343546762675873", "819269203286474309632", "98698960328223628470379", "12824232015954542746048512", "1787731339345567827140060737", "266157254062414638948185210880" ]
[ "nonn" ]
14
0
2
[ "A088690", "A161633", "A361182", "A380808", "A380826", "A380829", "A380830" ]
null
Seiichi Manyama, Feb 04 2025
2025-02-05T09:22:58
oeisdata/seq/A380/A380826.seq
65f240fce85e8a7af69575d1fe4a04f5
A380827
Least integer k such that the multiplicative group modulo n is a subgroup of the symmetric group S_k.
[ "1", "1", "2", "2", "4", "2", "5", "4", "5", "4", "7", "4", "7", "5", "6", "6", "16", "5", "11", "6", "7", "7", "13", "6", "9", "7", "11", "7", "11", "6", "10", "10", "9", "16", "9", "7", "13", "11", "9", "8", "13", "7", "12", "9", "9", "13", "25", "8", "12", "9", "18", "9", "17", "11", "11", "9", "13", "11", "31", "8", "12", "10", "10", "18", "11", "9", "16", "18", "15", "9", "14", "9", "17", "13", "11", "13", "12", "9", "18", "10", "29" ]
[ "nonn" ]
24
1
3
[ "A008475", "A282625", "A380222", "A380827" ]
null
Asher Gray, Feb 04 2025
2025-02-23T11:32:17
oeisdata/seq/A380/A380827.seq
3b66e928bf7d6ce06d31fc1a2da4c46e
A380828
Expansion of e.g.f. (1/x) * Series_Reversion( x * exp(-2*x) / (1 + x) ).
[ "1", "3", "26", "398", "8904", "264072", "9790192", "436382256", "22748241024", "1358633214080", "91503397265664", "6862436244211968", "567252637423922176", "51244493078278198272", "5023312927780022323200", "531082672018567209801728", "60239691905397303186849792", "7297357396264290237329473536" ]
[ "nonn" ]
12
0
2
[ "A088690", "A352448", "A376093", "A380808", "A380828", "A380830" ]
null
Seiichi Manyama, Feb 05 2025
2025-02-05T09:23:40
oeisdata/seq/A380/A380828.seq
6c00d13666a3b2f791138cbab36c34da
A380829
Expansion of e.g.f. (1/x) * Series_Reversion( x * exp(-3*x) / (1 + x*exp(-x)) ).
[ "1", "4", "45", "891", "25757", "986653", "47235873", "2718521725", "182963698521", "14107443728553", "1226582182222469", "118751669770995913", "12671598073554789909", "1477709279563430592877", "186988047586389278202633", "25518989446806209718773157", "3736444151435292273253963313", "584269287631534621583659461841" ]
[ "nonn" ]
9
0
2
[ "A361182", "A380826", "A380829", "A380830" ]
null
Seiichi Manyama, Feb 05 2025
2025-02-05T09:23:02
oeisdata/seq/A380/A380829.seq
eaebf49891e65bee5d0151d957d69204
A380830
Expansion of e.g.f. (1/x) * Series_Reversion( x * exp(-3*x) / (1 + x) ).
[ "1", "4", "47", "978", "29769", "1201728", "60656679", "3681441648", "261337079601", "21256149703680", "1949700750690879", "199146039242552064", "22420399033075845177", "2758645779752490872832", "368321963942753147683575", "53038788218443786432223232", "8194316429830951008255159009", "1352065789150879084276947222528" ]
[ "nonn" ]
12
0
2
[ "A088690", "A361182", "A376094", "A380826", "A380828", "A380829", "A380830" ]
null
Seiichi Manyama, Feb 05 2025
2025-02-05T09:23:06
oeisdata/seq/A380/A380830.seq
f4820c5ea0567e3067ada27b0a5336c1
A380831
Numbers k such that k^(k + 1) == k + 1 (mod 2*k + 1) while 2*k+1 is not prime.
[ "1023", "1638", "14670", "21399", "24570", "40290", "44178", "45375", "52326", "98046", "128499", "135975", "157410", "229494", "244998", "257223", "370875", "400302", "419430", "436590", "458163", "502326", "625974", "686826", "754854", "839270", "905786", "993510", "1102983", "1134546", "1142226", "1152083", "1193898", "1373238", "1374011" ]
[ "nonn" ]
5
1
1
[ "A047845", "A374913", "A380831" ]
null
Michel Marcus, Feb 05 2025
2025-02-05T09:02:50
oeisdata/seq/A380/A380831.seq
7d337174821493e93f58d24b1fd24f70
A380832
Number of points in Z^4 of norm <= n where the sum of the four entries is even.
[ "1", "1", "49", "169", "625", "1465", "3337", "5689", "10009", "15937", "24865", "35761", "51265", "69817", "94849", "124009", "161497", "204529", "260137", "320497", "394705", "478705", "577489", "687913", "819313", "960457", "1127785", "1309153", "1517161", "1742497", "2001505", "2273473", "2585905", "2920009", "3297337", "3700153", "4144105", "4618657", "5145865", "5703073" ]
[ "nonn" ]
17
0
3
[ "A055410", "A380832" ]
null
Steven Lu, Feb 05 2025
2025-02-12T14:22:37
oeisdata/seq/A380/A380832.seq
38049a4503f69bccc8d5504333d1ae28
A380833
a(n) is the number of divisors d of n satisfying (-d)^n mod n = d.
[ "0", "1", "0", "1", "0", "2", "0", "1", "0", "2", "0", "2", "0", "2", "1", "1", "0", "2", "0", "2", "0", "2", "0", "1", "0", "2", "0", "2", "0", "4", "0", "1", "0", "2", "1", "2", "0", "2", "0", "1", "0", "3", "0", "1", "0", "2", "0", "2", "0", "2", "0", "2", "0", "2", "0", "2", "0", "2", "0", "1", "0", "2", "0", "1", "0", "4", "0", "2", "0", "2", "0", "2", "0", "2", "0", "1", "0", "3", "0", "2", "0", "2", "0", "3", "0", "2", "0", "1", "0", "3", "1", "1", "0", "2", "0", "1", "0", "2", "0", "2" ]
[ "nonn" ]
18
1
6
[ "A000005", "A371883", "A380656", "A380833" ]
null
Juri-Stepan Gerasimov, Feb 06 2025
2025-02-06T12:28:35
oeisdata/seq/A380/A380833.seq
5f53a767cff1d5848542d3badf468695
A380834
First column of Kimberling's ESC array.
[ "1", "4", "7", "9", "11", "15", "17", "20", "22", "25", "27", "30", "33", "35", "38", "41", "43", "46", "49", "51", "53", "57", "59", "61", "64", "67", "69", "72", "75", "77", "79", "83", "85", "88", "90", "93", "95", "99", "101", "103", "106", "109", "111", "114", "117", "119", "121", "125", "127", "130", "132", "135", "137", "140", "143", "145", "148", "151", "153", "156" ]
[ "nonn" ]
19
1
2
[ "A380834", "A380835" ]
null
Jeffrey Shallit, Feb 05 2025
2025-02-06T09:26:02
oeisdata/seq/A380/A380834.seq
676278f936fec7f820df89796fa292b5
A380835
Second column of Kimberling's ESC array.
[ "2", "6", "12", "14", "18", "24", "28", "32", "36", "40", "44", "48", "54", "56", "62", "66", "70", "74", "80", "82", "86", "92", "96", "98", "104", "108", "112", "116", "122", "124", "128", "134", "138", "142", "146", "150", "154", "160", "164", "166", "172", "176", "180", "184", "190", "192", "196", "202", "206", "210", "214", "218", "222", "226", "232", "234", "240" ]
[ "nonn" ]
18
1
1
[ "A380834", "A380835" ]
null
Jeffrey Shallit, Feb 05 2025
2025-02-06T09:26:04
oeisdata/seq/A380/A380835.seq
b22830dbe1fdc7904fe8d7d07e0a1f4c
A380836
a(n) is the smallest k such that tau(2*k) is equal to 2^n, where tau = A000005.
[ "1", "3", "12", "60", "420", "3780", "41580", "540540", "8648640", "147026880", "2793510720", "64250746560", "1606268664000", "46581791256000", "1444035528936000", "53429314570632000", "2190601897395912000", "94195881588024216000", "4427206434637138152000", "216933115297219769448000", "11497455110752647780744000" ]
[ "nonn" ]
43
1
2
[ "A000005", "A000028", "A005843", "A037992", "A099777", "A380836" ]
null
Juri-Stepan Gerasimov, Feb 06 2025
2025-02-16T22:30:38
oeisdata/seq/A380/A380836.seq
da62a69db01aed02794139311c9e3834
A380837
Sequence Sg of the eight sequences defining the blocks of terms in A377091.
[ "4", "9", "20", "31", "42", "60", "81", "100", "121", "147", "183", "210", "241", "272", "307", "342", "400", "441", "484", "529", "576", "651", "703", "757", "813", "871", "931", "965", "1023", "1059", "1089", "1125", "1190", "1228", "1296", "1369", "1408", "1448", "1520", "1525", "1598", "1603", "1681", "1764", "1849", "1936", "2070", "2117", "2209", "2302" ]
[ "nonn" ]
10
1
1
[ "A377091", "A379066", "A379788", "A379789", "A379790", "A379791", "A379792", "A379793", "A379794", "A380837", "A380838" ]
null
Paolo Xausa, Feb 05 2025
2025-05-24T01:14:41
oeisdata/seq/A380/A380837.seq
c8be302d5adaaa9a55aee0d3547d1293
A380838
Values of terms in A380837 which are not in A379066.
[ "965", "1089", "1228", "1448", "1525", "1603", "2117", "2307", "2404", "2916", "8650", "8837", "12544", "12999", "13458", "14402", "17690", "17957", "20737", "39205", "50177", "54292", "55699", "60518", "64517", "65028", "66053", "70757", "71827", "72364", "75077", "80657", "82947", "83524", "85852", "104977", "133957", "135427", "136164", "141377" ]
[ "nonn", "changed" ]
8
1
1
[ "A377091", "A379066", "A380837", "A380838" ]
null
Paolo Xausa, Feb 05 2025
2025-07-09T05:07:55
oeisdata/seq/A380/A380838.seq
df3bb9d14ef55e5c4aadaf86d7a56c1e
A380839
Numerators of J(n) = Product_{p|n, p odd prime} (p - 1)/(p - 2).
[ "1", "1", "2", "1", "4", "2", "6", "1", "2", "4", "10", "2", "12", "6", "8", "1", "16", "2", "18", "4", "12", "10", "22", "2", "4", "12", "2", "6", "28", "8", "30", "1", "20", "16", "8", "2", "36", "18", "24", "4", "40", "12", "42", "10", "8", "22", "46", "2", "6", "4", "32", "12", "52", "2", "40", "6", "36", "28", "58", "8", "60", "30", "12", "1", "16", "20", "66", "16", "44", "8", "70", "2", "72", "36" ]
[ "nonn", "frac" ]
40
1
3
[ "A167864", "A173557", "A305444", "A307410", "A380839" ]
null
Artur Jasinski, Feb 05 2025
2025-05-30T23:15:50
oeisdata/seq/A380/A380839.seq
e4b513e6062d7f6670e5f04e2a4bb8c9
A380840
Decimal expansion of Sum_{p prime} 1/(p-1)^3.
[ "1", "1", "4", "7", "5", "2", "9", "0", "9", "7", "7", "5", "8", "5", "8", "0", "0", "4", "6", "9", "3", "3", "2", "8", "3", "8", "0", "6", "2", "8", "2", "1", "3", "0", "4", "0", "1", "6", "4", "4", "7", "6", "4", "7", "3", "5", "5", "2", "5", "1", "1", "2", "2", "5", "5", "2", "7", "5", "8", "2", "4", "1", "2", "3", "9", "5", "0", "5", "3", "3", "5", "9", "0", "4", "5", "5", "0", "4", "5", "4", "3", "1", "4", "7", "2", "6", "5", "2", "2", "8", "7", "3", "7", "2", "6", "9", "0", "9", "4", "6", "7", "5", "1", "6", "8", "0" ]
[ "nonn" ]
14
1
3
[ "A085541", "A085548", "A086242", "A136141", "A152441", "A154945", "A179119", "A324833", "A369632", "A380840" ]
null
Artur Jasinski, Mar 19 2025
2025-03-31T13:40:01
oeisdata/seq/A380/A380840.seq
5d868927ba7efb489ae58dd3ae2c69ae
A380841
Array read by ascending antidiagonals: A(n,k) = n! * [x^n] 1/(1 - x*exp(x))^k.
[ "1", "0", "1", "0", "1", "1", "0", "4", "2", "1", "0", "21", "10", "3", "1", "0", "148", "66", "18", "4", "1", "0", "1305", "560", "141", "28", "5", "1", "0", "13806", "5770", "1380", "252", "40", "6", "1", "0", "170401", "69852", "16095", "2776", "405", "54", "7", "1", "0", "2403640", "970886", "217458", "35940", "4940", "606", "70", "8", "1", "0", "38143377", "15228880", "3335745", "533304", "70045", "8088", "861", "88", "9", "1" ]
[ "nonn", "tabl" ]
15
0
8
[ "A000007", "A000012", "A001477", "A006153", "A028552", "A213643", "A377529", "A377530", "A379993", "A380841", "A380842", "A380843" ]
null
Stefano Spezia, Feb 05 2025
2025-02-06T10:23:26
oeisdata/seq/A380/A380841.seq
1e53b009ff01fd6d845a2a68c9b483c8
A380842
Main diagonal of the array A380841.
[ "1", "1", "10", "141", "2776", "70045", "2157156", "78452521", "3290644288", "156380715801", "8304267312100", "487328231729581", "31318669850761008", "2187567259278425557", "165011952533314548676", "13368463736048341225425", "1157693100510102752463616", "106719312722496774534400177", "10433609651067618426072766020" ]
[ "nonn" ]
14
0
3
[ "A213643", "A380841", "A380842" ]
null
Stefano Spezia, Feb 05 2025
2025-05-29T04:13:05
oeisdata/seq/A380/A380842.seq
2925e26e1df0b8415cf68e4b13eba00a
A380843
Antidiagonal sums of the array A380841.
[ "1", "1", "2", "7", "35", "237", "2040", "21255", "259591", "3633549", "57320398", "1005959831", "19436938571", "409965565469", "9372278051700", "230832086585495", "6093185704307967", "171604903098322813", "5136091192685429770", "162792009969153667111", "5447239135976543715731", "191888373741260775025741" ]
[ "nonn" ]
4
0
3
[ "A380841", "A380843" ]
null
Stefano Spezia, Feb 05 2025
2025-02-05T22:05:16
oeisdata/seq/A380/A380843.seq
457f7cddc795c6ddd804a239f53af709
A380844
The number of divisors of n that have the same binary weight as n.
[ "1", "2", "1", "3", "1", "2", "1", "4", "2", "2", "1", "3", "1", "2", "1", "5", "1", "4", "1", "3", "2", "2", "1", "4", "1", "2", "1", "3", "1", "2", "1", "6", "2", "2", "2", "6", "1", "2", "1", "4", "1", "4", "1", "3", "2", "2", "1", "5", "2", "2", "1", "3", "1", "2", "1", "4", "1", "2", "1", "3", "1", "2", "1", "7", "2", "4", "1", "3", "1", "4", "1", "8", "1", "2", "2", "3", "1", "2", "1", "5", "1", "2", "1", "6", "1", "2", "1" ]
[ "nonn", "base", "easy" ]
10
1
2
[ "A000005", "A000043", "A000120", "A000265", "A000396", "A007814", "A324392", "A325565", "A380844", "A380845" ]
null
Amiram Eldar, Feb 05 2025
2025-02-07T00:43:46
oeisdata/seq/A380/A380844.seq
2c59b13fbe56e9a8b20191710ef76fc4
A380845
The sum of divisors of n that have the same binary weight as n.
[ "1", "3", "3", "7", "5", "9", "7", "15", "12", "15", "11", "21", "13", "21", "15", "31", "17", "36", "19", "35", "28", "33", "23", "45", "25", "39", "27", "49", "29", "45", "31", "63", "36", "51", "42", "84", "37", "57", "39", "75", "41", "84", "43", "77", "60", "69", "47", "93", "56", "75", "51", "91", "53", "81", "55", "105", "57", "87", "59", "105", "61", "93", "63", "127", "70", "108" ]
[ "nonn", "base", "easy" ]
10
1
2
[ "A000120", "A000203", "A000265", "A000396", "A000668", "A007814", "A038712", "A380844", "A380845" ]
null
Amiram Eldar, Feb 05 2025
2025-02-07T00:43:53
oeisdata/seq/A380/A380845.seq
4bf5caf389f326bdf13f7b4ccf47b470
A380846
Numbers k such that A380845(k) = 2*k.
[ "18", "42", "90", "186", "196", "306", "378", "420", "534", "618", "654", "690", "762", "834", "868", "906", "1062", "1110", "1194", "1242", "1326", "1362", "1422", "1458", "1530", "1698", "1764", "1818", "1866", "2118", "2214", "2262", "2324", "2346", "2490", "2598", "2670", "2706", "2730", "2778", "2838", "2862", "2884", "2922", "2958", "2994", "3066", "3138" ]
[ "nonn", "base", "easy" ]
14
1
1
[ "A000203", "A000396", "A005100", "A005101", "A380845", "A380846", "A380847", "A380848" ]
null
Amiram Eldar, Feb 05 2025
2025-02-10T16:10:06
oeisdata/seq/A380/A380846.seq
1a196f523dcf8b9baf757aa8774aa049
A380847
Numbers k such that A380845(k) = 3*k.
[ "1800", "3720", "7560", "15240", "20832", "30600", "42336", "61320", "85344", "109320", "116040", "122760", "171360", "218760", "238920", "245640", "343392", "346440", "395880", "437640", "462600", "484680", "491400", "580680", "687456", "854760", "875400", "896520", "917880", "925320", "950520", "954120", "976200", "982920", "1011720" ]
[ "nonn", "base", "easy" ]
11
1
1
[ "A000203", "A005100", "A005820", "A068403", "A380845", "A380846", "A380847", "A380848" ]
null
Amiram Eldar, Feb 05 2025
2025-02-09T06:54:15
oeisdata/seq/A380/A380847.seq
320936cd694e0dd5995ff52a519c1f89
A380848
Numbers k such that A380845(k) = 4*k.
[ "123832800", "247695840", "268337160", "495421920", "536707080", "990874080", "1073446920", "1981778400", "2146926600", "3963587040", "4293885960", "7927204320", "8587804680", "15854438880", "17175642120", "31708908000", "34351317000", "63417846240", "68702666760", "124884879840", "126713795040", "126835722720" ]
[ "nonn", "base" ]
12
1
1
[ "A000203", "A005100", "A027687", "A068404", "A380845", "A380846", "A380847", "A380848" ]
null
Amiram Eldar, Feb 05 2025
2025-02-12T03:16:38
oeisdata/seq/A380/A380848.seq
d05da8a53700a26110a2c404ef2473c7
A380849
Lesser of a pair of amicable numbers k < m such that s(k) = m and s(m) = k, where s(k) = A380845(k) - k is the sum of aliquot divisors of k that have the same binary weight as k.
[ "27940", "112420", "150368", "156840", "225060", "450340", "569376", "925920", "1102200", "1211232", "1802020", "2196592", "2423648", "3377640", "3604260", "4612644", "4874400", "4949160", "5092440", "6375336", "6632808", "6786340", "7155940", "7208740", "7626900", "7685128", "9443060", "9569780", "9643400", "9678020" ]
[ "nonn", "base" ]
9
1
1
[ "A000203", "A002025", "A002046", "A380845", "A380846", "A380849", "A380850" ]
null
Amiram Eldar, Feb 05 2025
2025-02-07T00:44:34
oeisdata/seq/A380/A380849.seq
7e9ae6546750d582c78059979bf24b68
A380850
Greater of a pair of amicable numbers k < m such that s(k) = m and s(m) = k, where s(k) = A380845(k) - k is the sum of aliquot divisors of k that have the same binary weight as k.
[ "36068", "145124", "153670", "294075", "290532", "581348", "593100", "1099530", "2066625", "1237830", "2326244", "2338832", "2476870", "6393390", "4652772", "4883976", "6854625", "9279675", "9548325", "6514464", "11725857", "8760548", "9237668", "9305828", "9457356", "8717912", "12190132", "12353716", "10607740", "12493444" ]
[ "nonn", "base" ]
9
1
1
[ "A000203", "A002025", "A002046", "A380845", "A380846", "A380849", "A380850" ]
null
Amiram Eldar, Feb 06 2025
2025-02-07T00:44:41
oeisdata/seq/A380/A380850.seq
e554adf66c23b9e8ee23e98b78c930be
A380851
Riordan array ((1-x)^(m-1), x/(1-x)) with factor r^(2*n) on row n, for m = 3/2, r = 2.
[ "1", "-2", "4", "-2", "8", "16", "-4", "24", "96", "64", "-10", "80", "480", "640", "256", "-28", "280", "2240", "4480", "3584", "1024", "-84", "1008", "10080", "26880", "32256", "18432", "4096", "-264", "3696", "44352", "147840", "236544", "202752", "90112", "16384", "-858", "13728", "192192", "768768", "1537536", "1757184", "1171456", "425984", "65536" ]
[ "sign", "tabl" ]
25
0
2
[ "A002420", "A007318", "A097805", "A104712", "A104713", "A135278", "A159854", "A240530", "A380851" ]
null
Igor Victorovich Statsenko, Feb 06 2025
2025-03-02T02:45:21
oeisdata/seq/A380/A380851.seq
74a9180a364d1fc7f01482cd8bf5aa3c
A380852
a(1) = 2; thereafter a(n) is the least prime which is the sum of two or more consecutive primes starting with a(n-1).
[ "2", "5", "23", "83", "269", "1381", "7039", "21139", "105751", "317279", "7935833", "39679259", "357113983", "73923025091", "517461176119", "29495287085179", "1268297344683899", "21561054859629541", "280293713175186847", "33354951867847517227", "833873796696187941437", "120911700520947252047333", "5199203122400731838067259" ]
[ "nonn" ]
29
1
1
null
null
Andrey Samosyuk, Feb 06 2025
2025-03-26T22:29:18
oeisdata/seq/A380/A380852.seq
b3251fb3c921b220e4d46eb3b2cba65f
A380853
Number of ways to place six distinct positive integers on a triangle, three on the corners and three on the sides such that the sum of the three values on each side is n.
[ "0", "0", "0", "0", "0", "0", "0", "0", "1", "3", "5", "13", "14", "25", "37", "47", "58", "89", "98", "126", "159", "188", "219", "276", "303", "362", "423", "478", "536", "633", "688", "781", "881", "973", "1068", "1211", "1301", "1443", "1589", "1724", "1866", "2066", "2202", "2396", "2598", "2790", "2986", "3250", "3439", "3699", "3967", "4219", "4480", "4819", "5071" ]
[ "nonn", "easy" ]
46
1
10
[ "A342467", "A380105", "A380853" ]
null
Derek Holton and Alex Holton, Feb 06 2025
2025-03-13T06:08:14
oeisdata/seq/A380/A380853.seq
95db1221aa5785037d2f6c7c29acdea5
A380854
Integers m for which m = Sum (d_i + 1)^k, where m is k decimal digits long and d_i are the digits of m.
[ "141", "251", "560", "664807556", "424710875510", "863812804425", "137134427278403350052", "366828486147473227474", "186740753582576522645847734" ]
[ "nonn", "more", "base" ]
8
1
1
[ "A005188", "A261433", "A380810", "A380854" ]
null
Chai Wah Wu, Feb 06 2025
2025-02-07T13:10:53
oeisdata/seq/A380/A380854.seq
0937b2edc69db29179615331b80a0109
A380855
The unique sequence starting with a(0) = 1, a(1) = 0 and partial sums are 1 followed by the sequence terms themselves repeated in successive blocks a(0..2^k-1) for k >= 0.
[ "1", "0", "0", "-1", "1", "-1", "0", "-1", "2", "-1", "0", "-1", "2", "-2", "1", "-1", "2", "-1", "0", "-1", "2", "-2", "1", "-1", "3", "-3", "1", "-1", "3", "-4", "3", "-2", "2", "-1", "0", "-1", "2", "-2", "1", "-1", "3", "-3", "1", "-1", "3", "-4", "3", "-2", "3", "-3", "1", "-1", "3", "-4", "3", "-2", "4", "-6", "4", "-2", "4", "-7", "7", "-5", "3", "-1", "0", "-1", "2", "-2", "1", "-1", "3", "-3", "1", "-1", "3", "-4", "3", "-2", "3", "-3", "1", "-1", "3", "-4", "3" ]
[ "sign", "easy" ]
49
0
9
[ "A053645", "A380855" ]
null
Thomas Scheuerle, Feb 06 2025
2025-02-09T12:20:52
oeisdata/seq/A380/A380855.seq
e3ef18f6396b9baeff28dcf618e91176
A380856
In the binary expansion of n, arrange bits row-wise in a binary tree which is complete except for the last row and then read those bits in pre-order.
[ "0", "1", "2", "3", "4", "5", "6", "7", "8", "10", "9", "11", "12", "14", "13", "15", "16", "18", "20", "22", "17", "19", "21", "23", "24", "26", "28", "30", "25", "27", "29", "31", "32", "33", "36", "37", "40", "41", "44", "45", "34", "35", "38", "39", "42", "43", "46", "47", "48", "49", "52", "53", "56", "57", "60", "61", "50", "51", "54", "55", "58", "59", "62", "63", "64", "65", "66", "67", "72" ]
[ "nonn", "look", "base" ]
39
0
3
[ "A000079", "A000225", "A007283", "A053738", "A053754", "A335040", "A378496", "A379905", "A380856" ]
null
Darío Clavijo, Feb 06 2025
2025-02-18T07:29:13
oeisdata/seq/A380/A380856.seq
34270d0ea9654cb70015f93e91190557
A380857
Squares of numbers that are neither squarefree nor prime powers.
[ "144", "324", "400", "576", "784", "1296", "1600", "1936", "2025", "2304", "2500", "2704", "2916", "3136", "3600", "3969", "4624", "5184", "5625", "5776", "6400", "7056", "7744", "8100", "8464", "9216", "9604", "9801", "10000", "10816", "11664", "12544", "13456", "13689", "14400", "15376", "15876", "17424", "18225", "18496", "19600", "20736" ]
[ "nonn", "easy" ]
16
1
1
[ "A013661", "A059404", "A082020", "A085548", "A120944", "A126706", "A154945", "A177492", "A286708", "A359280", "A362605", "A378768", "A380857" ]
null
Michael De Vlieger, Feb 06 2025
2025-02-08T23:34:27
oeisdata/seq/A380/A380857.seq
2f8c5d37c9c7382b994f3c44c7fdcde1
A380858
a(n) is the number of primes p <= n such that p^(p + n) == p (mod p + n).
[ "0", "0", "2", "1", "2", "1", "1", "2", "1", "3", "2", "3", "1", "3", "2", "3", "2", "4", "1", "3", "1", "3", "1", "6", "0", "6", "1", "4", "2", "7", "1", "3", "0", "6", "3", "6", "1", "5", "2", "5", "2", "8", "1", "5", "1", "5", "1", "8", "0", "6", "2", "5", "1", "9", "0", "8", "1", "5", "3", "12", "1", "8", "1", "7", "2", "11", "1", "8", "2", "8", "2", "10", "1", "6", "0", "9", "1", "12", "1", "7", "1", "5", "1", "13", "0", "9", "3", "6", "1", "15" ]
[ "nonn", "look" ]
18
1
3
[ "A000040", "A371883", "A380858" ]
null
Juri-Stepan Gerasimov, Feb 06 2025
2025-03-13T08:56:37
oeisdata/seq/A380/A380858.seq
8fd80e9b95d4150f36854e4e41a36fa5
A380859
Number of minimum connected dominating sets in the n-triangular honeycomb obtuse knight graph.
[ "1", "0", "0", "0", "0", "630", "36", "4", "12", "4232", "770" ]
[ "nonn", "more" ]
43
1
6
null
null
Eric W. Weisstein, Mar 05 2025
2025-05-30T10:07:37
oeisdata/seq/A380/A380859.seq
ad45bd5ab0b315551dc62b23ee7f1292
A380860
Triangle read by rows: T(n,m) (0<=m<=n) = number of positive n-digit numbers that have exactly m copies of a specific, previously selected positive base-10 digit among its digits.
[ "1", "8", "1", "72", "17", "1", "648", "225", "26", "1", "5832", "2673", "459", "35", "1", "52488", "29889", "6804", "774", "44", "1", "472392", "321489", "91125", "13770", "1170", "53", "1", "4251528", "3365793", "1141614", "215055", "24300", "1647", "62", "1", "38263752", "34543665", "13640319", "3077109", "433755", "39123", "2205", "71", "1", "344373768", "349156737", "157306536", "41334300", "6980904", "785862", "58968", "2844", "80", "1" ]
[ "nonn", "base", "tabl" ]
25
0
2
[ "A052268", "A055275", "A081044", "A380860" ]
null
Peter Starek, Feb 06 2025
2025-02-07T16:34:14
oeisdata/seq/A380/A380860.seq
96c7f64f6f6cc8a9d5cce234a93637d1
A380861
Decimal expansion of the smallest acute vertex angle, in radians, in a deltoidal hexecontahedron face.
[ "1", "1", "8", "3", "0", "3", "6", "7", "2", "8", "4", "2", "0", "0", "8", "3", "4", "1", "4", "7", "9", "0", "1", "3", "6", "1", "8", "6", "7", "9", "9", "8", "8", "7", "8", "6", "5", "0", "5", "4", "8", "2", "0", "6", "6", "8", "3", "6", "8", "4", "0", "6", "3", "5", "9", "7", "6", "6", "7", "9", "2", "8", "5", "3", "3", "5", "5", "6", "4", "0", "7", "3", "1", "4", "3", "9", "9", "2", "7", "5", "3", "9", "6", "4", "9", "4", "8", "8", "0", "3" ]
[ "nonn", "cons", "easy" ]
13
1
3
[ "A002163", "A379385", "A379386", "A379387", "A379388", "A379389", "A380861", "A380862", "A380863" ]
null
Paolo Xausa, Feb 06 2025
2025-02-08T03:43:57
oeisdata/seq/A380/A380861.seq
45593ac57a4766d72e012c663c5ec259
A380862
Decimal expansion of the largest acute angles, in radians, in a deltoidal hexecontahedron face.
[ "1", "5", "1", "7", "9", "8", "5", "3", "7", "7", "4", "6", "0", "2", "1", "5", "4", "6", "3", "6", "0", "2", "1", "9", "1", "3", "5", "7", "3", "8", "6", "0", "7", "2", "4", "4", "8", "1", "7", "1", "2", "3", "3", "3", "8", "2", "5", "2", "7", "1", "6", "7", "2", "3", "0", "1", "0", "8", "0", "7", "6", "0", "2", "2", "4", "5", "5", "8", "8", "5", "1", "8", "3", "5", "3", "0", "5", "5", "1", "6", "4", "4", "8", "8", "2", "5", "1", "1", "8", "9" ]
[ "nonn", "cons", "easy" ]
11
1
2
[ "A020762", "A379385", "A379386", "A379387", "A379388", "A379389", "A380861", "A380862", "A380863" ]
null
Paolo Xausa, Feb 06 2025
2025-02-08T03:43:47
oeisdata/seq/A380/A380862.seq
4654b792b00a033c007af12daa0a5bed
A380863
Decimal expansion of the obtuse vertex angle, in radians, in a deltoidal hexecontahedron face.
[ "2", "0", "6", "4", "1", "7", "7", "8", "2", "3", "8", "3", "9", "0", "7", "2", "1", "3", "4", "9", "3", "0", "7", "6", "7", "8", "6", "4", "9", "8", "6", "9", "7", "3", "0", "0", "6", "9", "9", "7", "0", "5", "1", "3", "6", "5", "3", "2", "7", "4", "7", "0", "8", "2", "1", "9", "6", "6", "9", "4", "4", "2", "8", "6", "3", "4", "8", "2", "2", "1", "7", "1", "4", "0", "7", "1", "3", "8", "7", "1", "6", "7", "8", "4", "1", "5", "5", "7", "8", "3" ]
[ "nonn", "cons", "easy" ]
8
1
1
[ "A002163", "A379385", "A379386", "A379387", "A379388", "A379389", "A380861", "A380862", "A380863" ]
null
Paolo Xausa, Feb 07 2025
2025-02-08T03:43:41
oeisdata/seq/A380/A380863.seq
3993aede067fffd417f105480cb2c43d
A380864
a(n) = [x^n] sqrt(1 - 4*x)/(1 - 8*x). Row sums of A380865.
[ "1", "6", "46", "364", "2902", "23188", "185420", "1483096", "11863910", "94908420", "759257636", "6074027496", "48592102396", "388736403144", "3109889739352", "24879112565936", "199032881137798", "1592262978387044", "12738103567806772", "101904827587176776", "815238617162887828", "6521908924174861784" ]
[ "nonn" ]
11
0
2
[ "A380864", "A380865" ]
null
Peter Luschny, Feb 06 2025
2025-02-08T04:53:51
oeisdata/seq/A380/A380864.seq
5e82d3d5e6cd420d26edaea81bf91b1a
A380865
Triangle read by rows: T(n, k) = 2^(2*n)*JacobiP(n - k, k, -1/2 - n, -1).
[ "1", "2", "4", "6", "24", "16", "20", "120", "160", "64", "70", "560", "1120", "896", "256", "252", "2520", "6720", "8064", "4608", "1024", "924", "11088", "36960", "59136", "50688", "22528", "4096", "3432", "48048", "192192", "384384", "439296", "292864", "106496", "16384", "12870", "205920", "960960", "2306304", "3294720", "2928640", "1597440", "491520", "65536" ]
[ "nonn", "tabl" ]
11
0
2
[ "A038234", "A097807", "A128908", "A380851", "A380864", "A380865" ]
null
Peter Luschny, Feb 07 2025
2025-02-08T04:48:20
oeisdata/seq/A380/A380865.seq
d5f25d64607f3136b3d394222233a2d6
A380866
a(n) is the least m > 0 such that sigma(m) - 2m = A140863(n).
[ "18", "196", "100", "36", "15376", "162", "1352", "72", "968", "200", "392", "13456", "144", "8450", "1032256", "400", "119072", "324", "8464", "288", "1936", "5776", "2704", "4624", "111392", "450", "800", "1458", "9604", "2450", "1568", "882", "2500", "576", "648", "89888", "3872", "5408", "1600", "70688", "2178", "9248", "11552", "11025", "59168", "53792", "3136", "16928", "1152", "900", "43808", "26912", "3042", "30752" ]
[ "nonn" ]
8
1
1
[ "A000203", "A033880", "A140863", "A380866" ]
null
M. F. Hasler, Mar 10 2025
2025-03-12T08:18:45
oeisdata/seq/A380/A380866.seq
46170d145e98eeccbd3861368b35f86c
A380867
Numbers k such that one can make a rectangle from a chain of linked rods of length 1, 2, 3, ..., k, with perimeter equal to the total length.
[ "8", "15", "20", "24", "27", "32", "35", "39", "44", "48", "51", "55", "56", "63", "68", "75", "80", "84", "87", "92", "95", "99", "104", "111", "115", "116", "119", "120", "123", "124", "128", "132", "135", "140", "143", "144", "147", "152", "155", "159", "160", "164", "168", "171", "175", "176", "183", "184", "188", "195", "200", "203", "204", "207", "208", "212", "215", "216", "219", "220", "224", "231", "235", "236" ]
[ "nonn", "nice" ]
15
1
1
[ "A000217", "A334720", "A380867" ]
null
Ali Sada and M. F. Hasler, Mar 14 2025
2025-05-15T21:51:54
oeisdata/seq/A380/A380867.seq
67d57345ecf7bf85962db1848f44a76e
A380868
Number of distinct solutions {n1, n2, n3, n4} to the problem of forming a rectangle with sides made of linked rods of length 1, ..., n.
[ "0", "0", "0", "0", "0", "0", "0", "1", "0", "0", "0", "0", "0", "0", "1", "0", "0", "0", "0", "3", "0", "0", "0", "1", "0", "0", "3", "0", "0", "0", "0", "1", "0", "0", "6", "0", "0", "0", "6", "0", "0", "0", "0", "6", "0", "0", "0", "1", "0", "0", "3", "0", "0", "0", "3", "3", "0", "0", "0", "0", "0", "0", "1", "0", "0", "0", "0", "3", "0", "0", "0", "0", "0", "0", "6", "0", "0", "0", "0", "6", "0", "0", "0", "10", "0", "0", "3", "0", "0", "0", "0", "3", "0", "0", "1", "0", "0", "0", "15" ]
[ "nonn" ]
24
1
20
[ "A000217", "A334720", "A380867", "A380868" ]
null
M. F. Hasler, Mar 14 2025
2025-03-22T18:40:39
oeisdata/seq/A380/A380868.seq
df64871688b1311f33c5e8f5043dd4b4
A380869
Numbers k such that one can make a rectangle from a chain of linked rods of lengths 1, 2, 3, ..., k, with perimeter equal to the total length, and with one side consisting of a single rod.
[ "8", "15", "20", "24", "27", "35", "39", "80", "84", "104", "143", "215", "220", "252", "264", "351", "363", "459", "476" ]
[ "nonn", "more" ]
12
1
1
[ "A000217", "A334720", "A380867", "A380868", "A380869" ]
null
Ali Sada and M. F. Hasler, Mar 14 2025
2025-03-18T10:52:19
oeisdata/seq/A380/A380869.seq
8719eebdd9c548877046909c64eb12e2
A380870
a(n) = A381798(n) - A361373(n) - 1.
[ "0", "0", "0", "0", "0", "0", "0", "0", "0", "1", "0", "0", "0", "0", "3", "0", "0", "2", "0", "1", "4", "6", "0", "0", "0", "8", "0", "1", "0", "1", "0", "0", "3", "3", "7", "2", "0", "13", "0", "1", "0", "4", "0", "7", "6", "6", "0", "1", "0", "15", "14", "8", "0", "13", "3", "0", "15", "23", "0", "1", "0", "0", "5", "0", "5", "7", "0", "3", "9", "12", "0", "2", "0", "30", "18", "14", "10", "6", "0", "3", "0", "14", "0" ]
[ "nonn" ]
12
1
15
[ "A000961", "A024619", "A361373", "A377485", "A380870", "A381750", "A381798", "A381799" ]
null
Michael De Vlieger, Apr 08 2025
2025-04-12T12:42:53
oeisdata/seq/A380/A380870.seq
0d793d7dad780449e6f08f2a8bbf6ec3
A380871
Limit of the trajectory of n under A380873: concatenate sum and product of digits, if it ends on a fixed point, otherwise the least element of the limit cycle.
[ "0", "50", "70", "70", "70", "80", "1236", "40", "88", "10", "10", "50", "50", "60", "20", "50", "70", "50", "70", "10", "20", "50", "70", "50", "70", "80", "70", "10", "80", "90", "30", "60", "50", "70", "60", "90", "90", "40", "88", "90", "40", "20", "70", "60", "70", "20", "70", "40", "70", "10", "50", "50", "80", "90", "20", "80", "50", "50", "80", "40", "60", "70", "70", "90", "70", "50", "1236", "70", "70", "70", "70", "50", "10" ]
[ "nonn" ]
9
0
2
[ "A007953", "A007954", "A062237", "A380871", "A380872", "A380873" ]
null
M. F. Hasler, Apr 02 2025
2025-04-04T22:36:35
oeisdata/seq/A380/A380871.seq
e7db19bfb50c0174e79c57ef44b9c4f0
A380872
Infinite square array, where row r >= 0 is the orbit of r under the map A380873: concatenate(sum of digits, product of digits).
[ "0", "0", "1", "0", "11", "2", "0", "21", "22", "3", "0", "32", "44", "33", "4", "0", "56", "816", "69", "44", "5", "0", "1130", "1548", "1554", "816", "55", "6", "0", "50", "18160", "15100", "1548", "1025", "66", "7", "0", "50", "160", "70", "18160", "80", "1236", "77", "8", "0", "50", "70", "70", "160", "80", "1236", "1449", "88", "9", "0", "50", "70", "70", "70", "80", "1236", "18144", "1664", "99", "10", "0", "50", "70", "70", "70", "80", "1236", "18128", "17144", "1881", "10", "11", "0", "50", "70", "70", "70", "80", "1236", "20128", "17112", "1864" ]
[ "nonn", "base", "tabl" ]
15
0
5
[ "A007953", "A007954", "A271220", "A271268", "A380872", "A380873" ]
null
M. F. Hasler, Apr 01 2025
2025-04-04T22:37:13
oeisdata/seq/A380/A380872.seq
a5208f08920a8fbe0d7d96ade131a676
A380873
Concatenate sum and product of decimal digits of n.
[ "0", "11", "22", "33", "44", "55", "66", "77", "88", "99", "10", "21", "32", "43", "54", "65", "76", "87", "98", "109", "20", "32", "44", "56", "68", "710", "812", "914", "1016", "1118", "30", "43", "56", "69", "712", "815", "918", "1021", "1124", "1227", "40", "54", "68", "712", "816", "920", "1024", "1128", "1232", "1336", "50", "65", "710", "815", "920", "1025", "1130", "1235", "1340", "1445", "60" ]
[ "nonn", "base" ]
16
0
2
[ "A007953", "A007954", "A062237", "A271220", "A271268", "A380872", "A380873" ]
null
M. F. Hasler, Apr 01 2025
2025-04-12T18:19:25
oeisdata/seq/A380/A380873.seq
035e73fa79b7aabf09358af29bf01cbe
A380874
Indices of odd values > 1 in A067044 (least k such that k*n has only even digits).
[ "16", "54", "58", "74", "76", "92", "94", "96", "98", "118", "126", "128", "136", "148", "154", "156", "158", "160", "162", "164", "168", "176", "182", "184", "186", "188", "196", "216", "218", "238", "252", "254", "272", "274", "276", "292", "294", "296", "298", "316", "318", "326", "346", "352", "364", "366", "372", "376", "382", "384", "386", "388", "392" ]
[ "nonn", "base" ]
4
1
1
[ "A067044", "A380874" ]
null
M. F. Hasler, Mar 07 2025
2025-03-07T09:24:12
oeisdata/seq/A380/A380874.seq
008862a91d4e2c368cb6f34026661c59
A380875
Indices of triangular numbers (A000217) which are also perimeters of integer-sided right triangles (A010814).
[ "8", "15", "20", "23", "24", "27", "32", "35", "39", "44", "47", "48", "51", "55", "56", "59", "60", "63", "64", "68", "71", "72", "75", "76", "79", "80", "84", "87", "91", "92", "95", "96", "99", "104", "111", "112", "115", "116", "119", "120", "123", "124", "128", "132", "135", "139", "140", "143", "144", "147", "152", "155", "159", "160", "164", "167", "168", "171", "175", "176", "179", "180", "183", "184", "187", "188" ]
[ "nonn" ]
13
1
1
[ "A000217", "A010814", "A380875", "A382268" ]
null
M. F. Hasler, Mar 20 2025
2025-04-02T10:21:59
oeisdata/seq/A380/A380875.seq
ffe2a390abe5e32d27aa7c7b7e7593e0
A380876
a(1) = 1; a(2) = 4; for n > 2, a(n) = least unused positive y such that gcd(y,n-1) > 1 and |y-n| > 1.
[ "1", "4", "6", "9", "2", "10", "3", "14", "12", "15", "5", "22", "8", "26", "7", "18", "20", "34", "16", "38", "24", "27", "11", "46", "21", "30", "13", "33", "32", "58", "25", "62", "28", "36", "17", "40", "39", "74", "19", "42", "35", "82", "45", "86", "48", "50", "23", "94", "44", "56", "54", "57", "60", "106", "51", "65", "49", "63", "29", "118", "52", "122", "31", "66", "68", "55", "64", "134", "72" ]
[ "nonn" ]
19
1
2
null
null
Ali Sada, Feb 06 2025
2025-02-18T18:38:18
oeisdata/seq/A380/A380876.seq
7dbb52b2e61007663b735860b1493435
A380877
Primes p where the prime race 12m+1 versus 12m+7 is tied.
[ "2", "3", "5", "13", "17", "433", "457", "461" ]
[ "nonn" ]
10
1
1
[ "A007351", "A068228", "A068229", "A379989", "A380333", "A380877" ]
null
Ya-Ping Lu, Feb 06 2025
2025-03-03T10:47:28
oeisdata/seq/A380/A380877.seq
e1d0c945553a0025e682c1cbc6417d16
A380878
Numbers k such that k*(k+1) shares no decimal digits with k or k+1.
[ "2", "3", "4", "5", "6", "7", "8", "15", "17", "18", "22", "24", "32", "33", "34", "37", "42", "43", "44", "45", "47", "48", "53", "54", "55", "56", "57", "58", "65", "66", "76", "77", "78", "83", "85", "92", "143", "144", "148", "154", "156", "165", "175", "188", "194", "195", "222", "232", "237", "242", "257", "265", "292", "294", "303", "307", "312", "313", "322", "332", "333", "334", "343", "344", "375", "377", "387", "392" ]
[ "nonn", "base" ]
14
1
1
[ "A375211", "A380878" ]
null
Robert Israel, Feb 07 2025
2025-02-07T16:00:50
oeisdata/seq/A380/A380878.seq
f1d12fa7f9577a386b435b58877d3ed1
A380879
Expansion of e.g.f. (1/x) * Series_Reversion( x * exp(-2*x*exp(x)) ).
[ "1", "2", "16", "230", "4888", "138442", "4916140", "210270734", "10530743632", "604747157138", "39185881490644", "2828691317839510", "225137088955561144", "19588316964130880474", "1849745928662841982588", "188421660506420000503838", "20594905554562935801454240", "2404374864844251715105658146" ]
[ "nonn" ]
10
0
2
[ "A162695", "A360474", "A380879", "A380880" ]
null
Seiichi Manyama, Feb 07 2025
2025-02-07T05:36:43
oeisdata/seq/A380/A380879.seq
f2394a180937875c17e5697c774b2a7b
A380880
Expansion of e.g.f. (1/x) * Series_Reversion( x * exp(-3*x*exp(x)) ).
[ "1", "3", "33", "657", "19317", "756663", "37153071", "2196991317", "152107121481", "12074764795947", "1081507189545219", "107911010079715857", "11871250914793342797", "1427601609871824349407", "186326851375925627135127", "26232637698244127999077677", "3962908338833364902518738449", "639433805204122165558890771027" ]
[ "nonn" ]
11
0
2
[ "A162695", "A380879", "A380880", "A380881" ]
null
Seiichi Manyama, Feb 07 2025
2025-02-07T05:36:34
oeisdata/seq/A380/A380880.seq
4b03b19ec98db58b1e97fdbe86fd5e0a
A380881
E.g.f. A(x) satisfies A(x) = exp( x * A(x)^3 * exp(x * A(x)^3) ).
[ "1", "1", "9", "163", "4541", "171781", "8231395", "478055299", "32642065433", "2562896897353", "227510655792191", "22533214047347455", "2463465770439307045", "294676777871863052173", "38284087227668033391515", "5368383942726216941810971", "808133883137288259018215345", "129988823008132636178027546257" ]
[ "nonn" ]
11
0
3
[ "A162695", "A360474", "A362656", "A380880", "A380881" ]
null
Seiichi Manyama, Feb 07 2025
2025-02-07T05:36:28
oeisdata/seq/A380/A380881.seq
194d41e8d74788700ae0cb658b818765
A380882
Centered square numbers which are sphenic numbers.
[ "1105", "2665", "3445", "7565", "8845", "14965", "15665", "16745", "17485", "18241", "20605", "22685", "23545", "27145", "28085", "32005", "32513", "35113", "37265", "48985", "50245", "50881", "55445", "56785", "62305", "71065", "74885", "78013", "80401", "81205", "84461", "85285", "88621", "89465", "109045", "111865", "113765", "116645", "118585", "119561" ]
[ "nonn" ]
13
1
1
[ "A001844", "A007304", "A027862", "A370795", "A371016", "A380882" ]
null
Massimo Kofler, Feb 07 2025
2025-03-02T23:54:35
oeisdata/seq/A380/A380882.seq
2f936f4c1fa7643c72a993eee5d58c2d
A380883
a(n) is the smallest multiple of prime(n) which contains every decimal digit of prime(n), including repetitions.
[ "12", "30", "15", "70", "110", "130", "170", "190", "230", "290", "310", "370", "164", "344", "470", "530", "295", "610", "670", "710", "730", "790", "830", "890", "679", "1010", "1030", "1070", "1090", "1130", "1270", "1310", "1370", "1390", "1490", "1510", "1570", "1630", "1670", "1730", "1790", "1810", "1719", "1930", "1379", "1990", "2110", "2230", "2270", "2290", "2330", "2390", "2410", "1255", "2570", "2367", "2690" ]
[ "nonn", "base" ]
13
1
1
[ "A000040", "A087217", "A380811", "A380883" ]
null
David James Sycamore, Feb 07 2025
2025-02-23T11:24:42
oeisdata/seq/A380/A380883.seq
7b134967715fa939a3a7177e3ea751a7
A380884
Primes p such that there is an m < 10 for which m*p contains every decimal digit of p.
[ "2", "5", "41", "43", "59", "97", "191", "197", "251", "263", "373", "401", "443", "491", "499", "599", "653", "691", "967", "991", "997", "1481", "1901", "1913", "1997", "2549", "2551", "2591", "3067", "3491", "4001", "4013", "4493", "4793", "4931", "4943", "4967", "4973", "4993", "4999", "5021", "5443", "5647", "6053", "6361", "6521", "6703", "6991", "7489", "7901", "7951", "7993" ]
[ "nonn", "base" ]
13
1
1
[ "A000040", "A380811", "A380883", "A380884" ]
null
David James Sycamore, Feb 07 2025
2025-02-23T11:18:23
oeisdata/seq/A380/A380884.seq
6cf78ad4c6390aab43e8c3bcd4a3ed47
A380885
a(n) is the smallest multiple m*n (m > 1) of n which contains every decimal digit of n, including repetitions.
[ "10", "12", "30", "24", "15", "36", "70", "48", "90", "100", "110", "120", "130", "140", "105", "160", "170", "108", "190", "120", "126", "220", "230", "240", "125", "260", "270", "280", "290", "300", "310", "320", "330", "340", "315", "360", "370", "380", "390", "240", "164", "294", "344", "440", "405", "460", "470", "384", "294", "150", "153", "520", "530", "540" ]
[ "nonn", "base" ]
24
1
1
[ "A087217", "A380885" ]
null
David James Sycamore, Feb 07 2025
2025-02-23T11:19:08
oeisdata/seq/A380/A380885.seq
ad4e49ed4b6d1f9d735abac120547270
A380886
Triangle T(n,k), 1<=k<=n: column k are the coefficients of the INVERT transform of Sum_{i=1..k} i*x^i.
[ "1", "1", "3", "1", "5", "8", "1", "11", "17", "21", "1", "21", "42", "50", "55", "1", "43", "100", "128", "138", "144", "1", "85", "235", "323", "358", "370", "377", "1", "171", "561", "813", "923", "965", "979", "987", "1", "341", "1331", "2043", "2378", "2510", "2559", "2575", "2584", "1", "683", "3158", "5150", "6125", "6527", "6681", "6737", "6755", "6765", "1", "1365", "7503", "12967", "15772", "16972", "17441", "17617", "17680", "17700", "17711" ]
[ "nonn", "tabl", "easy" ]
10
1
3
[ "A001045", "A001906", "A054452", "A101822", "A322059", "A380886" ]
null
R. J. Mathar, Feb 07 2025
2025-02-07T09:11:52
oeisdata/seq/A380/A380886.seq
d09bad25055209b87b05265239342f1d
A380887
a(n) is the smallest positive integer s that can be partitioned into n positive integers whose product is s * 100^(n-1).
[ "1", "400", "525", "644", "759", "864", "972", "1089", "1188", "1296", "1403", "1508", "1612", "1722", "1827", "1932", "2040", "2145", "2250", "2354", "2457", "2565", "2668", "2772", "2880", "2988", "3087", "3192", "3294", "3399", "3498", "3604", "3705", "3810", "3915", "4018", "4116", "4221", "4323", "4425", "4536", "4635", "4732", "4836", "4940" ]
[ "nonn" ]
81
1
2
[ "A380887", "A381187", "A381619", "A381621", "A382547" ]
null
Markus Sigg, Feb 07 2025
2025-06-04T00:18:41
oeisdata/seq/A380/A380887.seq
5cec13e0627f55b79b59de205add5ce7
A380888
Integers k such that k = Sum k/(p_i + j), where p_i are the prime factors of k (with multiplicity). Case j = -1.
[ "2", "9", "75", "625", "1029", "1365", "8575", "11375", "24843", "32955", "73815", "117649", "156065", "207025", "274625", "483153", "599781", "615125", "866481", "1008273", "1252815", "1337505", "1343433", "1553937", "1782105", "1955085", "2061345", "2840383", "3051015", "3432165", "3737085", "3767855", "4026275", "4998175" ]
[ "nonn" ]
20
1
1
[ "A036878", "A380888", "A380889", "A380900", "A380901", "A380923", "A380928" ]
null
Paolo P. Lava, Feb 07 2025
2025-04-25T18:18:26
oeisdata/seq/A380/A380888.seq
dd07096eb86a873495a63b5bbf24d026
A380889
Integers k such that k = Sum k/(p_i + j), where p_i are the prime factors of k (with multiplicity). Case j = 1.
[ "8", "81", "90", "100", "132", "1125", "1250", "1323", "1470", "1485", "1650", "2156", "2178", "2420", "2898", "3220", "6348", "6612", "12948", "15625", "18375", "20625", "21609", "24010", "24255", "26950", "27225", "30250", "35574", "35937", "36225", "39930", "40250", "47334", "47817", "53130", "58564", "71415", "74385", "77924", "79350" ]
[ "nonn", "easy" ]
9
1
1
[ "A380888", "A380889", "A380900", "A380901", "A380923", "A380928" ]
null
Paolo P. Lava, Feb 07 2025
2025-03-02T23:48:02
oeisdata/seq/A380/A380889.seq
a6f1c0a08c8af26e8ce35d30c04054ef
A380890
Triangle T(n,k) read by rows: the number of graphs with n nodes which are enriched cycles (necklaces) and the elements in the cycle are marked linear chains up to length k.
[ "1", "1", "2", "1", "2", "4", "1", "3", "5", "7", "1", "3", "7", "9", "12", "1", "5", "14", "18", "21", "24", "1", "5", "19", "29", "35", "38", "42", "1", "8", "35", "56", "71", "77", "81", "85", "1", "10", "60", "100", "133", "148", "156", "160", "165", "1", "15", "107", "192", "264", "297", "317", "325", "330", "335", "1", "19", "187", "361", "511", "586", "630", "650", "660", "665", "671", "1", "31", "352", "714", "1041", "1206", "1306", "1350", "1375", "1385", "1391", "1397" ]
[ "nonn", "tabl" ]
10
1
3
[ "A000358", "A322059", "A380890" ]
null
R. J. Mathar, Feb 07 2025
2025-02-10T04:57:58
oeisdata/seq/A380/A380890.seq
a2c15475f4699e77dd35ecd3785d89c8
A380891
If n mod 2 = 0 then a(n) = floor(n^(1/3)) else a(n) = floor(n^(4/3)).
[ "0", "1", "1", "4", "1", "8", "1", "13", "2", "18", "2", "24", "2", "30", "2", "36", "2", "43", "2", "50", "2", "57", "2", "65", "2", "73", "2", "81", "3", "89", "3", "97", "3", "105", "3", "114", "3", "123", "3", "132", "3", "141", "3", "150", "3", "160", "3", "169", "3", "179", "3", "189", "3", "199", "3", "209", "3", "219", "3", "229", "3", "240", "3", "250", "4", "261", "4", "272" ]
[ "nonn", "easy" ]
40
0
4
[ "A048766", "A094683", "A129011", "A380891", "A381246", "A383135" ]
null
Vikram Prasad, Feb 08 2025
2025-05-05T16:44:45
oeisdata/seq/A380/A380891.seq
248fbea11b5857f4a6f719ebbac94520
A380892
Hexagonal numbers that are abundant.
[ "66", "120", "276", "378", "630", "780", "1128", "1326", "1540", "1770", "2016", "2556", "2850", "3160", "3486", "3828", "4560", "4950", "5778", "6216", "7140", "7626", "7875", "8646", "9180", "9730", "10296", "10878", "12090", "12720", "14028", "14706", "15400", "16110", "16836", "17955", "18336", "19110", "19900", "20706", "21528", "21945", "23220", "24090", "24976" ]
[ "nonn" ]
19
1
1
[ "A000384", "A005101", "A063734", "A074315", "A117794", "A379264", "A380892" ]
null
Massimo Kofler, Feb 07 2025
2025-02-24T21:22:40
oeisdata/seq/A380/A380892.seq
9e8e333ba7d40d7fdf64956b591fde5b
A380893
Triangle read by rows: T(n,m) = number of solid partitions of n with shape of a plane partition of m.
[ "1", "1", "3", "1", "3", "6", "1", "6", "6", "13", "1", "6", "15", "13", "24", "1", "9", "21", "37", "24", "48", "1", "9", "30", "58", "75", "48", "86", "1", "12", "39", "95", "132", "159", "86", "160", "1", "12", "54", "128", "231", "297", "299", "160", "282", "1", "15", "63", "197", "345", "552", "593", "574", "282", "500", "1", "15", "81", "251", "546", "873", "1156", "1180", "1038", "500", "859", "1", "18", "96", "345", "771", "1452", "1933", "2390", "2208", "1874", "859", "1479", "1", "18", "114", "432", "1110", "2151", "3340", "4154", "4614", "4082", "3268", "1479", "2485", "1", "21", "132", "558", "1491", "3276", "5214", "7430", "8310", "8758", "7276", "5685", "2485", "4167" ]
[ "nonn", "tabl" ]
11
1
3
[ "A000219", "A000293", "A094504", "A380893" ]
null
Wouter Meeussen, Feb 07 2025
2025-02-10T01:05:29
oeisdata/seq/A380/A380893.seq
8bbbbcf99af5c25450581704f81ed38a
A380894
a(1) = 0; a(2) = 1; for n > 2, a(n) = a(n-1) + least unique positive difference of two earlier terms.
[ "0", "1", "2", "4", "7", "11", "16", "22", "32", "44", "58", "76", "96", "121", "147", "177", "208", "241", "277", "314", "352", "392", "435", "480", "527", "579", "636", "694", "754", "815", "878", "943", "1014", "1086", "1159", "1235", "1312", "1390", "1470", "1551", "1634", "1719", "1806", "1894", "1989", "2085", "2185", "2286", "2389", "2494", "2600", "2709" ]
[ "nonn" ]
12
1
3
[ "A000045", "A002858", "A380894" ]
null
Felix Huber, Feb 10 2025
2025-03-04T23:01:38
oeisdata/seq/A380/A380894.seq
3768d127c6eac6e4ab863ec45d837a6c
A380895
Decimal expansion of (sqrt(17) + 1)/(4*sqrt(17)).
[ "3", "1", "0", "6", "3", "3", "9", "0", "6", "2", "5", "9", "0", "8", "3", "2", "4", "3", "3", "7", "9", "7", "2", "6", "6", "1", "5", "5", "2", "9", "0", "3", "0", "5", "4", "4", "4", "8", "7", "4", "5", "8", "8", "1", "2", "1", "3", "7", "8", "4", "7", "3", "5", "9", "3", "2", "9", "3", "9", "1", "6", "7", "0", "1", "9", "2", "5", "7", "2", "8", "5", "8", "0", "3", "4", "3", "7", "6", "7", "8", "8", "1", "4", "0", "9", "9", "7", "9", "9", "4", "8", "6", "4", "8", "6", "3", "0", "0", "4", "3" ]
[ "nonn", "cons", "easy" ]
13
0
1
[ "A010473", "A222132", "A380895", "A380896" ]
null
Stefano Spezia, Feb 07 2025
2025-02-08T12:59:46
oeisdata/seq/A380/A380895.seq
a07b88a61bd9698f996e17a8e9c81199
A380896
Decimal expansion of (sqrt(17) - 1)/(4*sqrt(17)).
[ "1", "8", "9", "3", "6", "6", "0", "9", "3", "7", "4", "0", "9", "1", "6", "7", "5", "6", "6", "2", "0", "2", "7", "3", "3", "8", "4", "4", "7", "0", "9", "6", "9", "4", "5", "5", "5", "1", "2", "5", "4", "1", "1", "8", "7", "8", "6", "2", "1", "5", "2", "6", "4", "0", "6", "7", "0", "6", "0", "8", "3", "2", "9", "8", "0", "7", "4", "2", "7", "1", "4", "1", "9", "6", "5", "6", "2", "3", "2", "1", "1", "8", "5", "9", "0", "0", "2", "0", "0", "5", "1", "3", "5", "1", "3", "6", "9", "9", "5", "6" ]
[ "nonn", "cons", "easy" ]
12
0
2
[ "A010473", "A222132", "A380895", "A380896" ]
null
Stefano Spezia, Feb 07 2025
2025-02-08T13:00:55
oeisdata/seq/A380/A380896.seq
992a23c90552b70879e779146d86b254
A380897
Decimal expansion of (108)^(1/5).
[ "2", "5", "5", "0", "8", "4", "9", "0", "0", "1", "2", "5", "1", "5", "8", "1", "6", "6", "5", "7", "3", "3", "0", "9", "5", "7", "0", "0", "3", "8", "5", "9", "9", "8", "5", "4", "6", "5", "8", "9", "8", "0", "0", "1", "6", "7", "3", "8", "3", "9", "6", "4", "5", "4", "7", "3", "7", "8", "0", "1", "9", "6", "3", "6", "2", "1", "1", "4", "3", "4", "4", "6", "8", "6", "0", "6", "9", "4", "7", "1", "3", "1", "1", "0", "3", "5", "1", "4", "8", "7", "3", "0", "7", "9", "5", "8", "6", "4", "4", "0" ]
[ "nonn", "cons", "easy" ]
8
1
1
[ "A222132", "A380897" ]
null
Stefano Spezia, Feb 07 2025
2025-02-08T03:43:33
oeisdata/seq/A380/A380897.seq
9e78fe86bb83c8be9b25ccbd9578e6e9
A380898
Decimal expansion of 2^(8/3).
[ "6", "3", "4", "9", "6", "0", "4", "2", "0", "7", "8", "7", "2", "7", "9", "7", "8", "9", "9", "0", "0", "6", "8", "2", "2", "5", "5", "7", "0", "8", "9", "2", "3", "3", "0", "4", "1", "5", "6", "5", "9", "7", "3", "3", "1", "1", "5", "9", "9", "4", "1", "2", "0", "3", "9", "2", "3", "3", "1", "4", "3", "0", "4", "7", "3", "0", "0", "8", "6", "6", "0", "2", "2", "4", "9", "6", "8", "7", "6", "6", "9", "3", "0", "9", "4", "1", "7", "6", "8", "5", "3", "0", "4", "8", "8", "8", "3", "8", "2", "8" ]
[ "nonn", "cons", "easy" ]
11
1
1
[ "A002580", "A010588", "A010603", "A380898" ]
null
Stefano Spezia, Feb 07 2025
2025-02-08T09:02:32
oeisdata/seq/A380/A380898.seq
730588bd30a825d08f1ecf3843054522
A380899
Three-Catalan Triangle read by rows, for n>=0 and k>=0.
[ "1", "1", "1", "1", "1", "4", "9", "11", "10", "6", "3", "1", "34", "90", "120", "120", "96", "64", "35", "15", "5", "1", "364", "1000", "1400", "1505", "1351", "1044", "700", "406", "202", "84", "28", "7", "1", "4269", "11925", "17225", "19425", "18657", "15753", "11845", "7965", "4785", "2553", "1197", "485", "165", "45", "9", "1" ]
[ "nonn", "tabf" ]
12
0
6
[ "A005721", "A008287", "A380899" ]
null
Michel Marcus, Feb 07 2025
2025-02-10T03:13:12
oeisdata/seq/A380/A380899.seq
9ce4091333894c24ade6267a16c8ecea
A380900
Integers k such that k = Sum k/(p_i + j), where p_i are the prime factors of k (with multiplicity). Case j = -2.
[ "3", "125", "16807", "29155", "33275", "50575", "90475", "7761061", "8857805", "11796113", "13463065", "20462645", "21102389", "24084445", "35496425", "36606185", "63500525", "65485805", "73776725", "99798725", "113597825", "117779585", "178056445", "193155305", "200599525", "203878325", "204311525", "251218345" ]
[ "nonn" ]
9
1
1
[ "A380888", "A380889", "A380900", "A380901", "A380923", "A380928" ]
null
Paolo P. Lava, Feb 09 2025
2025-03-02T23:48:09
oeisdata/seq/A380/A380900.seq
09821e196997573611b1de5d787cdaaa
A380901
Integers k such that k = Sum k/(p_i + j), where p_i are the prime factors of k (with multiplicity). Case j = 2.
[ "16", "243", "78125", "120393", "166725", "177957", "316953", "792585", "1478925", "40353607", "55883275", "59648043", "77389375", "82602975", "88167807", "106237047", "107171875", "114391875", "122098275", "128153375", "130323843", "147121275", "157032603", "177471875", "189427875", "190142667", "203739375", "217464975" ]
[ "nonn" ]
8
1
1
[ "A380888", "A380889", "A380900", "A380901", "A380923", "A380928" ]
null
Paolo P. Lava, Mar 03 2025
2025-03-16T08:08:05
oeisdata/seq/A380/A380901.seq
cfc87bcf7d4b5e4985283131e942e8ac
A380902
Integers k with at least 1 proper factorization for which the sum of the squares of the factors equals k.
[ "16", "27", "48", "54", "270", "528", "1755", "7216", "7830", "11934", "69168", "81702", "100368", "264654", "340470", "559899", "1397808", "1586340", "1695195", "3837510", "3918420", "8989110", "9815568", "13010448", "15812550", "19468816", "26302590", "75872430", "132825616", "133529580", "180280539", "271165488" ]
[ "nonn" ]
24
1
1
[ "A001694", "A005117", "A162247", "A190882", "A380760", "A380902" ]
null
Charles L. Hohn, Feb 07 2025
2025-03-25T08:59:35
oeisdata/seq/A380/A380902.seq
444f965ce1b83a467f77bee1edecfb67
A380903
Least positive k such that n^n * k^k - 1 is a prime, or 0 if no such k exists.
[ "2", "2", "1", "2", "3", "4", "10147", "24" ]
[ "nonn", "hard", "more" ]
8
0
1
[ "A228175", "A231119", "A231735", "A380903" ]
null
Jason Yuen, Feb 07 2025
2025-02-10T09:33:11
oeisdata/seq/A380/A380903.seq
58b0d4300c855a408e045cebff6ef21c
A380904
An integer sequence giving a counterexample to a theorem of Szüsz and Volkmann.
[ "0", "10", "20", "30", "40", "50", "60", "70", "80", "90", "100", "110", "120", "130", "140", "150", "160", "170", "180", "190", "200", "210", "220", "230", "240", "250", "260", "270", "280", "290", "300", "310", "320", "330", "340", "350", "360", "370", "380", "390", "400", "410", "420", "430", "440", "450", "460", "470", "480", "490", "500", "510", "520", "530", "540", "550", "560", "570", "580", "590", "600", "610", "620", "630", "640", "650", "660", "670", "680", "690", "700", "710", "720", "730", "740", "750", "760", "770", "780", "790", "800", "810", "820", "830", "840", "850", "860", "870", "880", "890", "900", "1000", "1100", "1200", "1300", "1400", "1500", "1600", "1700", "1800", "1900", "2000", "2100", "2200", "2300", "2400", "2500", "2600", "2700", "2800", "2900", "3000" ]
[ "nonn" ]
44
9
2
[ "A008592", "A380904" ]
null
John M. Campbell, Feb 07 2025
2025-03-03T14:52:26
oeisdata/seq/A380/A380904.seq
d8afe39b66087f0f52b8f67c7aba3e90
A380905
Smallest number k such that k^(2*3^n) - 6 is prime.
[ "3", "5", "23", "7", "433", "2447", "9377", "82597", "134687" ]
[ "nonn", "more", "hard" ]
151
0
1
[ "A008776", "A025192", "A028879", "A239414", "A380905", "A382246" ]
null
Jakub Buczak, Feb 07 2025
2025-04-17T09:34:12
oeisdata/seq/A380/A380905.seq
da64f5507018741c4d5c049941aae20b
A380906
Primes avoiding the digits 3 and 5.
[ "2", "7", "11", "17", "19", "29", "41", "47", "61", "67", "71", "79", "89", "97", "101", "107", "109", "127", "149", "167", "179", "181", "191", "197", "199", "211", "227", "229", "241", "269", "271", "277", "281", "401", "409", "419", "421", "449", "461", "467", "479", "487", "491", "499", "601", "607", "617", "619", "641", "647", "661", "677", "691", "701", "709", "719", "727", "761", "769", "787", "797" ]
[ "base", "nonn" ]
27
1
1
[ "A000040", "A020462", "A038611", "A038613", "A329760", "A380906" ]
null
Vincenzo Librandi, Feb 09 2025
2025-02-12T21:53:10
oeisdata/seq/A380/A380906.seq
bdef3d8e3be619f0306ca3ec509bc4af
A380907
Decimal expansion of 1/(2^(1/4)*sqrt(1+Pi/4)).
[ "6", "2", "9", "3", "2", "4", "9", "6", "3", "4", "2", "1", "0", "1", "9", "3", "1", "0", "2", "6", "2", "2", "8", "6", "3", "4", "3", "7", "7", "8", "8", "2", "1", "7", "2", "5", "4", "9", "2", "6", "6", "6", "4", "4", "2", "4", "2", "8", "0", "1", "0", "9", "3", "9", "6", "7", "8", "3", "8", "5", "8", "1", "0", "4", "6", "2", "5", "0", "6", "5", "2", "1", "9", "8", "1", "7", "9", "2", "5", "2", "5", "5", "6", "9", "3", "3", "5", "8", "5", "5", "9", "5", "9", "5", "8", "5", "7", "9", "5", "0" ]
[ "nonn", "cons" ]
7
0
1
[ "A003881", "A010767", "A019704", "A228497", "A380907" ]
null
Stefano Spezia, Feb 08 2025
2025-02-08T09:01:26
oeisdata/seq/A380/A380907.seq
26a637aaa3a1c7eb88fa7767d1dae651
A380908
Decimal expansion of lim_{s->1} (zeta(s) - Pi^(s/2)/((s-1)*Gamma(s/2))) (negated).
[ "9", "7", "6", "9", "0", "4", "2", "9", "1", "0", "3", "3", "8", "7", "8", "9", "6", "6", "1", "8", "5", "6", "8", "9", "7", "5", "2", "0", "9", "3", "5", "0", "4", "7", "0", "8", "3", "7", "8", "0", "6", "7", "8", "7", "2", "8", "4", "7", "9", "4", "9", "2", "4", "0", "4", "7", "4", "6", "0", "7", "9", "2", "7", "7", "8", "7", "0", "2", "8", "6", "4", "3", "5", "2", "3", "2", "7", "5", "4", "2", "0", "0", "2", "9", "2", "0", "1", "4", "3", "0", "4", "8", "8", "2", "9" ]
[ "nonn", "cons" ]
18
0
1
[ "A001620", "A114864", "A155968", "A380908" ]
null
Peter Luschny, Mar 04 2025
2025-03-05T10:42:49
oeisdata/seq/A380/A380908.seq
faa1a8f53d9ccb34c10ab939d711a7c2
A380909
a(n) = numerator(n!! / (n - 1)!!).
[ "1", "1", "2", "3", "8", "15", "16", "35", "128", "315", "256", "693", "1024", "3003", "2048", "6435", "32768", "109395", "65536", "230945", "262144", "969969", "524288", "2028117", "4194304", "16900975", "8388608", "35102025", "33554432", "145422675", "67108864", "300540195", "2147483648", "9917826435", "4294967296", "20419054425" ]
[ "nonn", "frac" ]
27
0
3
[ "A004730", "A004731", "A006882", "A095987", "A380909", "A380910" ]
null
Peter Luschny, Feb 09 2025
2025-02-11T07:13:35
oeisdata/seq/A380/A380909.seq
c2ca6f30571d8236cf547293f028b73d
A380910
a(n) = denominator(n!! / (n - 1)!!).
[ "1", "1", "1", "2", "3", "8", "5", "16", "35", "128", "63", "256", "231", "1024", "429", "2048", "6435", "32768", "12155", "65536", "46189", "262144", "88179", "524288", "676039", "4194304", "1300075", "8388608", "5014575", "33554432", "9694845", "67108864", "300540195", "2147483648", "583401555", "4294967296", "2268783825", "17179869184" ]
[ "nonn", "frac" ]
15
0
4
[ "A004730", "A004731", "A380909", "A380910" ]
null
Peter Luschny, Feb 09 2025
2025-02-11T04:41:29
oeisdata/seq/A380/A380910.seq
c0841aec87f8f958028b12b0d52c0728
A380911
Triangle read by rows: Row n is the initial segment [1, 2, ..., n] sorted into lexicographic order defined by the binary representation of the terms.
[ "1", "1", "2", "1", "2", "3", "1", "2", "4", "3", "1", "2", "4", "5", "3", "1", "2", "4", "5", "3", "6", "1", "2", "4", "5", "3", "6", "7", "1", "2", "4", "8", "5", "3", "6", "7", "1", "2", "4", "8", "9", "5", "3", "6", "7", "1", "2", "4", "8", "9", "5", "10", "3", "6", "7", "1", "2", "4", "8", "9", "5", "10", "11", "3", "6", "7", "1", "2", "4", "8", "9", "5", "10", "11", "3", "6", "12", "7" ]
[ "nonn", "tabl", "base" ]
14
1
3
[ "A007088", "A380911" ]
null
Peter Luschny, Feb 08 2025
2025-02-08T16:06:03
oeisdata/seq/A380/A380911.seq
8a664417e827f20c7152a5a408de3591
A380912
Two-Catalan Triangle read by rows, for n>=0 and k>=0.
[ "1", "1", "1", "1", "3", "6", "6", "3", "1", "15", "36", "40", "29", "15", "5", "1", "91", "232", "280", "238", "154", "76", "28", "7", "1", "603", "1585", "2025", "1890", "1398", "837", "405", "155", "45", "9", "1", "4213", "11298", "15026", "14938", "12078", "8162", "4642", "2211", "869", "274", "66", "11", "1", "30537", "83097", "113841", "118482", "102102", "75075", "47619", "26091", "12285", "4914", "1638", "441", "91", "13", "1" ]
[ "nonn", "tabf" ]
7
0
5
[ "A027907", "A089942", "A380899", "A380912" ]
null
Michel Marcus, Feb 08 2025
2025-02-08T11:11:47
oeisdata/seq/A380/A380912.seq
f158e4f95375c8bb73c28b6d589f123c
A380913
Squarefree semiprimes that are centered triangular numbers.
[ "10", "46", "85", "166", "235", "274", "514", "694", "901", "1135", "1219", "1306", "1585", "1891", "2461", "2839", "3106", "3385", "3826", "3979", "4135", "5311", "5674", "6049", "6835", "7246", "8551", "9481", "10966", "11485", "11749", "12286", "12559", "13969", "15151", "15454", "17335", "18649", "18985", "19666", "21421", "21781", "22879", "23626" ]
[ "nonn" ]
11
1
1
[ "A005448", "A006881", "A184481", "A359624", "A359845", "A380913" ]
null
Massimo Kofler, Feb 08 2025
2025-02-15T23:06:22
oeisdata/seq/A380/A380913.seq
895e514ae1b22120089732c1894752ae
A380914
E.g.f. A(x) satisfies A(x) = exp(x / (1 - x*A(x))) / (1 - x*A(x)).
[ "1", "2", "11", "115", "1797", "37621", "990313", "31452905", "1171010809", "50029903081", "2413119476781", "129719605920565", "7690829719605541", "498579900892422077", "35086898369381747281", "2663953520081549084401", "217057092837921132411249", "18892120969438125131207377", "1749385548844357561820688853" ]
[ "nonn" ]
8
0
2
[ "A380663", "A380769", "A380914", "A380915" ]
null
Seiichi Manyama, Feb 08 2025
2025-02-08T10:30:06
oeisdata/seq/A380/A380914.seq
33682bd3961fb5d02414465fafb31c17