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A002201 | Superior highly composite numbers: positive integers n for which there is an e > 0 such that d(n)/n^e >= d(k)/k^e for all k > 1, where the function d(n) counts the divisors of n (A000005). | [
"2",
"6",
"12",
"60",
"120",
"360",
"2520",
"5040",
"55440",
"720720",
"1441440",
"4324320",
"21621600",
"367567200",
"6983776800",
"13967553600",
"321253732800",
"2248776129600",
"65214507758400",
"195643523275200",
"6064949221531200"
] | [
"nonn",
"nice"
] | 64 | 0 | 5 | [
"A000005",
"A000705",
"A002110",
"A002182",
"A002201",
"A003418",
"A004490",
"A072938",
"A094348",
"A106037"
] | [
"M1591",
"N0620"
] | N. J. A. Sloane | 2025-02-16T08:32:25 | oeisdata/seq/A002/A002201.seq | 571ead4d012cb9999aeb665fea95e999 |
A002202 | Values taken by totient function phi(m) (A000010). | [
"1",
"2",
"4",
"6",
"8",
"10",
"12",
"16",
"18",
"20",
"22",
"24",
"28",
"30",
"32",
"36",
"40",
"42",
"44",
"46",
"48",
"52",
"54",
"56",
"58",
"60",
"64",
"66",
"70",
"72",
"78",
"80",
"82",
"84",
"88",
"92",
"96",
"100",
"102",
"104",
"106",
"108",
"110",
"112",
"116",
"120",
"126",
"128",
"130",
"132",
"136",
"138",
"140",
"144",
"148",
"150",
"156",
"160",
"162",
"164",
"166",
"168",
"172",
"176"
] | [
"nonn",
"nice"
] | 69 | 0 | 5 | [
"A000010",
"A002110",
"A002180",
"A002202",
"A005277",
"A006093",
"A007614",
"A007617",
"A032446",
"A058277",
"A083533",
"A264739"
] | [
"M0987",
"N0371"
] | N. J. A. Sloane | 2025-02-16T08:32:25 | oeisdata/seq/A002/A002202.seq | 5482ee5eafa963659768371cd845a4d6 |
A002203 | Companion Pell numbers: a(n) = 2*a(n-1) + a(n-2), a(0) = a(1) = 2. | [
"2",
"2",
"6",
"14",
"34",
"82",
"198",
"478",
"1154",
"2786",
"6726",
"16238",
"39202",
"94642",
"228486",
"551614",
"1331714",
"3215042",
"7761798",
"18738638",
"45239074",
"109216786",
"263672646",
"636562078",
"1536796802",
"3710155682",
"8957108166",
"21624372014",
"52205852194",
"126036076402",
"304278004998"
] | [
"nonn",
"easy"
] | 376 | 0 | 5 | [
"A000129",
"A001333",
"A002203",
"A002315",
"A003499",
"A077444",
"A100227",
"A244854",
"A302946"
] | [
"M0360",
"N0136"
] | N. J. A. Sloane | 2025-03-31T04:50:21 | oeisdata/seq/A002/A002203.seq | 0f5fbde5b0fa023486aade983e207911 |
A002204 | An ill-conditioned determinant. | [
"1",
"6",
"720",
"1512000",
"53343360000",
"31052236723200000",
"295415578275110092800000",
"45669605890716810734764032000000",
"114309087153174410876339218101043200000000",
"4620689394791469131629562883903627872698368000000000"
] | [
"nonn"
] | 28 | 0 | 5 | null | [
"M4313",
"N1806"
] | N. J. A. Sloane | 2023-10-14T23:49:55 | oeisdata/seq/A002/A002204.seq | 277848da9f50bb067738fdb16516caa9 |
A002205 | The RAND Corporation list of a million random digits. | [
"1",
"0",
"0",
"9",
"7",
"3",
"2",
"5",
"3",
"3",
"7",
"6",
"5",
"2",
"0",
"1",
"3",
"5",
"8",
"6",
"3",
"4",
"6",
"7",
"3",
"5",
"4",
"8",
"7",
"6",
"8",
"0",
"9",
"5",
"9",
"0",
"9",
"1",
"1",
"7",
"3",
"9",
"2",
"9",
"2",
"7",
"4",
"9",
"4",
"5",
"3",
"7",
"5",
"4",
"2",
"0",
"4",
"8",
"0",
"5",
"6",
"4",
"8",
"9",
"4",
"7",
"4",
"2",
"9",
"6",
"2",
"4",
"8",
"0",
"5",
"2",
"4",
"0",
"3",
"7",
"2",
"0",
"6",
"3",
"6",
"1",
"0",
"4",
"0",
"2",
"0",
"0",
"8",
"2",
"2",
"9",
"1",
"6",
"6"
] | [
"nonn",
"fini",
"full"
] | 29 | 0 | 5 | [
"A002205",
"A104183"
] | [
"M4594",
"N1959"
] | N. J. A. Sloane. Entry revised Jul 16 2009. | 2023-11-28T13:04:44 | oeisdata/seq/A002/A002205.seq | db6e0659d0eabe177d66d382f5ea9029 |
A002206 | Numerators of logarithmic numbers (also of Gregory coefficients G(n)). | [
"1",
"1",
"-1",
"1",
"-19",
"3",
"-863",
"275",
"-33953",
"8183",
"-3250433",
"4671",
"-13695779093",
"2224234463",
"-132282840127",
"2639651053",
"-111956703448001",
"50188465",
"-2334028946344463",
"301124035185049",
"-12365722323469980029"
] | [
"sign",
"frac",
"nice"
] | 192 | 0 | 5 | [
"A001620",
"A002206",
"A002207",
"A002208",
"A002209",
"A002657",
"A002790",
"A006232",
"A006233"
] | [
"M5066",
"N2194"
] | N. J. A. Sloane | 2025-02-16T08:32:25 | oeisdata/seq/A002/A002206.seq | 84c5074930c23e521c08dadce111ddec |
A002207 | Denominators of logarithmic numbers (also of Gregory coefficients G(n)). | [
"1",
"2",
"12",
"24",
"720",
"160",
"60480",
"24192",
"3628800",
"1036800",
"479001600",
"788480",
"2615348736000",
"475517952000",
"31384184832000",
"689762304000",
"32011868528640000",
"15613165568",
"786014494949376000",
"109285437800448000"
] | [
"nonn",
"frac",
"nice"
] | 120 | 0 | 5 | [
"A002206",
"A002207",
"A002208",
"A002209",
"A002657",
"A002790",
"A006232",
"A006233",
"A195189",
"A270857",
"A270859"
] | [
"M2017",
"N0797"
] | N. J. A. Sloane | 2025-02-16T08:32:25 | oeisdata/seq/A002/A002207.seq | 342a8703f6b09cf62f5f47cbe6b04e7a |
A002208 | Numerators of coefficients for numerical integration. | [
"1",
"1",
"5",
"3",
"251",
"95",
"19087",
"5257",
"1070017",
"25713",
"26842253",
"4777223",
"703604254357",
"106364763817",
"1166309819657",
"25221445",
"8092989203533249",
"85455477715379",
"12600467236042756559",
"1311546499957236437",
"8136836498467582599787"
] | [
"frac",
"nonn",
"easy",
"nice"
] | 100 | 0 | 5 | [
"A002206",
"A002207",
"A002208",
"A002209",
"A002657",
"A002790",
"A006232",
"A006233",
"A191578"
] | [
"M3737",
"N1527"
] | N. J. A. Sloane | 2025-01-05T19:51:32 | oeisdata/seq/A002/A002208.seq | 7ce91475847382a94aed9e4705396cd8 |
A002209 | Denominators of coefficients for numerical integration. | [
"1",
"2",
"12",
"8",
"720",
"288",
"60480",
"17280",
"3628800",
"89600",
"95800320",
"17418240",
"2615348736000",
"402361344000",
"4483454976000",
"98402304",
"32011868528640000",
"342372925440000",
"51090942171709440000",
"5377993912811520000",
"33720021833328230400000"
] | [
"nonn",
"frac",
"easy",
"nice"
] | 69 | 0 | 5 | [
"A002206",
"A002207",
"A002208",
"A002209",
"A002657",
"A002790",
"A006232",
"A006233"
] | [
"M2015",
"N0796"
] | N. J. A. Sloane | 2025-01-05T19:51:32 | oeisdata/seq/A002/A002209.seq | 3abaf07dd6620a51786f42b8e3726d67 |
A002210 | Decimal expansion of Khinchin's constant. | [
"2",
"6",
"8",
"5",
"4",
"5",
"2",
"0",
"0",
"1",
"0",
"6",
"5",
"3",
"0",
"6",
"4",
"4",
"5",
"3",
"0",
"9",
"7",
"1",
"4",
"8",
"3",
"5",
"4",
"8",
"1",
"7",
"9",
"5",
"6",
"9",
"3",
"8",
"2",
"0",
"3",
"8",
"2",
"2",
"9",
"3",
"9",
"9",
"4",
"4",
"6",
"2",
"9",
"5",
"3",
"0",
"5",
"1",
"1",
"5",
"2",
"3",
"4",
"5",
"5",
"5",
"7",
"2",
"1",
"8",
"8",
"5",
"9",
"5",
"3",
"7",
"1",
"5",
"2",
"0",
"0",
"2",
"8",
"0",
"1",
"1",
"4",
"1",
"1",
"7",
"4",
"9",
"3",
"1",
"8",
"4",
"7",
"6",
"9",
"7",
"9",
"9",
"5",
"1",
"5"
] | [
"nonn",
"cons",
"nice"
] | 96 | 0 | 5 | [
"A002210",
"A002211",
"A247038"
] | [
"M1564",
"N0609"
] | N. J. A. Sloane | 2025-02-16T08:32:25 | oeisdata/seq/A002/A002210.seq | c55c13462dffe78a2d4559e4a4eba05d |
A002211 | Continued fraction for Khintchine's constant. | [
"2",
"1",
"2",
"5",
"1",
"1",
"2",
"1",
"1",
"3",
"10",
"2",
"1",
"3",
"2",
"24",
"1",
"3",
"2",
"3",
"1",
"1",
"1",
"90",
"2",
"1",
"12",
"1",
"1",
"1",
"1",
"5",
"2",
"6",
"1",
"6",
"3",
"1",
"1",
"2",
"5",
"2",
"1",
"2",
"1",
"1",
"4",
"1",
"2",
"2",
"3",
"2",
"1",
"1",
"4",
"1",
"1",
"2",
"5",
"2",
"1",
"1",
"3",
"29",
"8",
"3",
"1",
"4",
"3",
"1",
"10",
"50",
"1",
"2",
"2",
"7",
"6",
"2",
"2",
"16",
"4",
"4",
"2",
"2",
"3",
"1",
"1",
"7",
"1",
"5",
"1",
"2",
"1",
"5",
"3",
"1"
] | [
"cofr",
"nonn",
"nice",
"easy"
] | 46 | 0 | 5 | [
"A002210",
"A002211"
] | [
"M0118",
"N0047"
] | N. J. A. Sloane | 2025-02-16T08:32:25 | oeisdata/seq/A002/A002211.seq | 42580e0a8209306e3689e5d590134a0e |
A002212 | Number of restricted hexagonal polyominoes with n cells. | [
"1",
"1",
"3",
"10",
"36",
"137",
"543",
"2219",
"9285",
"39587",
"171369",
"751236",
"3328218",
"14878455",
"67030785",
"304036170",
"1387247580",
"6363044315",
"29323149825",
"135700543190",
"630375241380",
"2938391049395",
"13739779184085",
"64430797069375",
"302934667061301",
"1427763630578197"
] | [
"nonn",
"easy",
"nice"
] | 323 | 0 | 5 | [
"A000108",
"A001006",
"A002212",
"A005572",
"A007317",
"A025230",
"A025238",
"A026375",
"A026376",
"A104259",
"A182401"
] | [
"M2850",
"N1145"
] | N. J. A. Sloane, Ronald C. Read | 2025-01-19T14:32:53 | oeisdata/seq/A002/A002212.seq | 1db8d012060381c27293fb7b10b0b770 |
A002213 | Number of tree-like polyhexes rooted at a hexagon and containing n hexagons. | [
"1",
"1",
"5",
"20",
"84",
"354",
"1540",
"6704",
"29610",
"131745",
"591049",
"2669346",
"12131148",
"55431285",
"254539897",
"1174027598",
"5436826110",
"25269402555",
"117838870833",
"551192276450",
"2585418254532",
"12158383558066",
"57313008207960"
] | [
"nonn",
"easy",
"changed"
] | 31 | 0 | 5 | [
"A002212",
"A002213",
"A002214",
"A002215",
"A002216"
] | [
"M3907",
"N1603"
] | N. J. A. Sloane | 2025-04-14T10:26:09 | oeisdata/seq/A002/A002213.seq | ff71bfbe2f9eaf9106a1dd8016fc7922 |
A002214 | Number of unrooted hexagonal polyominoes with n cells and no reflections allowed. | [
"1",
"1",
"2",
"7",
"18",
"64",
"226",
"856",
"3306",
"13249",
"53794",
"222717",
"933438",
"3960487",
"16970362",
"73381453",
"319817670",
"1403875491",
"6202064928",
"27559699507",
"123115236582",
"552654175124",
"2491870281372",
"11281732737898",
"51270697159708",
"233822055167579",
"1069835253304014",
"4909835353596645",
"22596879316320522"
] | [
"nonn"
] | 27 | 0 | 5 | null | [
"M1750",
"N0694"
] | N. J. A. Sloane | 2016-12-29T02:28:38 | oeisdata/seq/A002/A002214.seq | 1e713416fd9cda30d8b8b0e6f715ead6 |
A002215 | Number of polyhexes with n hexagons, having reflectional symmetry (see Harary and Read for precise definition). | [
"1",
"1",
"2",
"3",
"6",
"10",
"20",
"36",
"72",
"137",
"274",
"543",
"1086",
"2219",
"4438",
"9285",
"18570",
"39587",
"79174",
"171369",
"342738",
"751236",
"1502472",
"3328218",
"6656436",
"14878455",
"29756910",
"67030785",
"134061570",
"304036170",
"608072340",
"1387247580",
"2774495160"
] | [
"nonn"
] | 23 | 0 | 5 | [
"A002212",
"A002215"
] | [
"M0772",
"N0295"
] | N. J. A. Sloane | 2023-10-14T23:50:16 | oeisdata/seq/A002/A002215.seq | aa4941b894e1609cebaeaf0956aa86f0 |
A002216 | Harary-Read numbers: restricted hexagonal polyominoes (cata-polyhexes) with n cells. | [
"0",
"1",
"1",
"2",
"5",
"12",
"37",
"123",
"446",
"1689",
"6693",
"27034",
"111630",
"467262",
"1981353",
"8487400",
"36695369",
"159918120",
"701957539",
"3101072051",
"13779935438",
"61557789660",
"276327463180",
"1245935891922",
"5640868033058",
"25635351908072",
"116911035023017"
] | [
"nonn",
"easy",
"nice"
] | 55 | 0 | 5 | [
"A000228",
"A001998",
"A002212",
"A002213",
"A002214",
"A002215",
"A002216",
"A005963",
"A036359"
] | [
"M1426",
"N0562"
] | N. J. A. Sloane | 2025-02-16T08:32:25 | oeisdata/seq/A002/A002216.seq | 212c51980a5b6fa69dc395d919144ad2 |
A002217 | Starting with n, repeatedly calculate the sum of prime factors (with repetition) of the previous term, until reaching 0 or a fixed point: a(n) is the number of terms in the resulting sequence. | [
"2",
"1",
"1",
"1",
"1",
"2",
"1",
"3",
"3",
"2",
"1",
"2",
"1",
"4",
"4",
"4",
"1",
"4",
"1",
"4",
"3",
"2",
"1",
"4",
"3",
"5",
"4",
"2",
"1",
"3",
"1",
"3",
"5",
"2",
"3",
"3",
"1",
"4",
"5",
"2",
"1",
"3",
"1",
"5",
"2",
"4",
"1",
"2",
"5",
"3",
"5",
"2",
"1",
"2",
"5",
"2",
"3",
"2",
"1",
"3",
"1",
"6",
"2",
"3",
"5",
"5",
"1",
"4",
"6",
"5",
"1",
"3",
"1",
"6",
"2",
"2",
"5",
"5",
"1",
"2",
"3",
"2",
"1",
"5",
"3",
"3",
"4",
"2",
"1",
"2",
"5",
"5",
"3",
"6",
"5",
"2",
"1",
"5",
"2",
"5",
"1",
"3",
"1",
"2",
"5"
] | [
"nonn"
] | 44 | 0 | 5 | [
"A001414",
"A002217",
"A029908"
] | [
"M0150",
"N0060"
] | N. J. A. Sloane | 2025-02-16T08:32:25 | oeisdata/seq/A002/A002217.seq | 098569ee4996839c82d302963c66575a |
A002218 | Number of unlabeled nonseparable (or 2-connected) graphs (or blocks) with n nodes. | [
"0",
"1",
"1",
"3",
"10",
"56",
"468",
"7123",
"194066",
"9743542",
"900969091",
"153620333545",
"48432939150704",
"28361824488394169",
"30995890806033380784",
"63501635429109597504951",
"244852079292073376010411280",
"1783160594069429925952824734641",
"24603887051350945867492816663958981"
] | [
"nonn",
"nice"
] | 131 | 0 | 5 | [
"A000088",
"A001349",
"A002218",
"A004115",
"A006289",
"A006290",
"A010355",
"A013922",
"A241767",
"A325111",
"A339070",
"A339071"
] | [
"M2873",
"N1155"
] | N. J. A. Sloane | 2025-02-16T08:32:25 | oeisdata/seq/A002/A002218.seq | e4b894f7d2b873af0deb7d08b971648f |
A002219 | a(n) is the number of partitions of 2n that can be obtained by adding together two (not necessarily distinct) partitions of n. | [
"1",
"3",
"6",
"14",
"25",
"53",
"89",
"167",
"278",
"480",
"760",
"1273",
"1948",
"3089",
"4682",
"7177",
"10565",
"15869",
"22911",
"33601",
"47942",
"68756",
"96570",
"136883",
"189674",
"264297",
"362995",
"499617",
"678245",
"924522",
"1243098",
"1676339",
"2237625",
"2988351",
"3957525",
"5247500",
"6895946",
"9070144",
"11850304"
] | [
"nonn",
"nice"
] | 94 | 0 | 5 | [
"A000041",
"A002219",
"A002220",
"A002221",
"A002222",
"A006827",
"A046663",
"A064914",
"A108917",
"A122768",
"A213074",
"A213086",
"A235130",
"A237194",
"A237258",
"A276024",
"A276107",
"A284640",
"A300061",
"A304792",
"A357854",
"A357879",
"A357976"
] | [
"M2574",
"N1018"
] | N. J. A. Sloane | 2023-09-20T14:37:46 | oeisdata/seq/A002/A002219.seq | 97198713529057ce06410c890ce841f5 |
A002220 | a(n) is the number of partitions of 3n that can be obtained by adding together three (not necessarily distinct) partitions of n. | [
"1",
"4",
"10",
"30",
"65",
"173",
"343",
"778",
"1518",
"3088",
"5609",
"10959",
"18990",
"34441",
"58903",
"102044",
"167499",
"282519",
"451529",
"737208",
"1160102",
"1836910",
"2828466",
"4410990",
"6670202",
"10161240",
"15186315",
"22758131",
"33480869"
] | [
"nonn"
] | 43 | 0 | 5 | [
"A002219",
"A002220",
"A002221",
"A002222",
"A006827",
"A035470",
"A064914",
"A213074",
"A213086",
"A237258",
"A321142",
"A321451",
"A321452",
"A321453",
"A321454",
"A357976",
"A371731",
"A371737",
"A371783",
"A371792",
"A371795",
"A371796",
"A371955",
"A372122"
] | [
"M3395",
"N1374"
] | N. J. A. Sloane | 2024-04-21T23:50:54 | oeisdata/seq/A002/A002220.seq | 124e5d7c2e2b850eeee20203eb96c09f |
A002221 | a(n) is the number of partitions of 4n that can be obtained by adding together four (not necessarily distinct) partitions of n. | [
"1",
"5",
"15",
"55",
"140",
"448",
"1022",
"2710",
"6048",
"14114",
"28831",
"64091",
"123649",
"251295",
"476835",
"916972",
"1654044",
"3080159",
"5377431",
"9624588",
"16490017",
"28433473",
"47423409",
"80279375"
] | [
"nonn",
"more"
] | 26 | 0 | 5 | [
"A002219",
"A002220",
"A002221",
"A002222",
"A213074",
"A213086"
] | [
"M3861",
"N1583"
] | N. J. A. Sloane | 2016-05-24T05:28:48 | oeisdata/seq/A002/A002221.seq | 0f108fad9bff324d715a90a919456ec4 |
A002222 | a(n) is the number of partitions of 5n that can be obtained by adding together five (not necessarily distinct) partitions of n. | [
"1",
"6",
"21",
"91",
"266",
"994",
"2562",
"7764",
"19482",
"51212",
"116028",
"288541",
"612463",
"1375609",
"2862437",
"6036606",
"11846488",
"24080685",
"45506290"
] | [
"nonn",
"more"
] | 26 | 0 | 5 | [
"A000041",
"A002219",
"A002220",
"A002221",
"A002222",
"A213074",
"A213086"
] | [
"M4147",
"N1722"
] | N. J. A. Sloane | 2016-05-24T05:29:24 | oeisdata/seq/A002/A002222.seq | 4ca1e5edb21976f3812a56636d08acbc |
A002223 | Smallest prime p of form p = 8k-1 such that first n primes (p_1=2, ..., p_n) are quadratic residues mod p. | [
"7",
"23",
"71",
"311",
"479",
"1559",
"5711",
"10559",
"18191",
"31391",
"366791",
"366791",
"366791",
"4080359",
"12537719",
"30706079",
"36415991",
"82636319",
"120293879",
"120293879",
"131486759",
"131486759",
"2929911599",
"2929911599",
"7979490791",
"33857579279"
] | [
"nonn",
"easy",
"nice"
] | 25 | 0 | 5 | [
"A002223",
"A002224",
"A002225",
"A045535"
] | [
"M4382",
"N1843"
] | N. J. A. Sloane | 2017-10-19T03:13:42 | oeisdata/seq/A002/A002223.seq | 13068d4b9851411f3d10e54248b19558 |
A002224 | Smallest prime p of form p = 8k+1 such that first n primes (p_1=2, ..., p_n) are quadratic residues mod p. | [
"17",
"73",
"241",
"1009",
"2689",
"8089",
"33049",
"53881",
"87481",
"483289",
"515761",
"1083289",
"3818929",
"3818929",
"9257329",
"22000801",
"48473881",
"48473881",
"175244281",
"427733329",
"427733329",
"898716289",
"8114538721",
"9176747449",
"23616331489",
"23616331489",
"23616331489",
"196265095009",
"196265095009",
"196265095009",
"196265095009",
"2871842842801",
"2871842842801",
"2871842842801",
"26437680473689"
] | [
"nonn",
"nice"
] | 51 | 0 | 5 | [
"A002223",
"A002224",
"A002225",
"A002226"
] | [
"M5040",
"N2176"
] | N. J. A. Sloane | 2024-10-17T23:06:13 | oeisdata/seq/A002/A002224.seq | d59af6f84824ee13fcb8db1e2f75428c |
A002225 | a(n) is the smallest prime p such that each of the first n primes has three cube roots mod p. | [
"31",
"307",
"643",
"5113",
"21787",
"39199",
"360007",
"360007",
"4775569",
"10318249",
"10318249",
"65139031",
"387453811",
"913900417",
"2278522747",
"2741702809",
"25147657981",
"118748663779",
"156776294593",
"747206701687",
"1151810360731",
"1151810360731",
"1151810360731"
] | [
"nonn",
"nice",
"more"
] | 40 | 0 | 5 | [
"A002223",
"A002224",
"A002225",
"A002226",
"A002227",
"A002228",
"A014752",
"A014753",
"A040044",
"A060363",
"A060364",
"A147972"
] | [
"M5224",
"N2274"
] | N. J. A. Sloane | 2024-04-11T10:10:54 | oeisdata/seq/A002/A002225.seq | 96a71484fd0accdc14cf422b58af8e48 |
A002226 | Smallest prime p such that first n primes (p_1=2, ..., p_n) are quintic residues mod p. | [
"151",
"431",
"6581",
"67651",
"241981",
"2081921",
"3395921",
"116900011",
"650086271",
"858613901",
"11736494711",
"50888057851",
"303855349271",
"2459339487751",
"3167880361091"
] | [
"nonn",
"nice",
"more"
] | 23 | 0 | 5 | [
"A002223",
"A002224",
"A002225",
"A002226",
"A002227"
] | [
"M5402",
"N2348"
] | N. J. A. Sloane | 2024-04-08T21:30:33 | oeisdata/seq/A002/A002226.seq | 89b2016ee93892cacdb7e7e5d4361185 |
A002227 | Smallest prime p such that first n primes (p_1=2, ..., p_n) are 7th power residues mod p. | [
"631",
"5531",
"72661",
"865957",
"2375059",
"32353609",
"175175603",
"945552637",
"945552637",
"54144188771",
"688203780167",
"2701344818803"
] | [
"nonn",
"more"
] | 24 | 0 | 5 | [
"A002223",
"A002224",
"A002225",
"A002226",
"A002227",
"A002228"
] | [
"M5466"
] | N. J. A. Sloane | 2024-04-13T01:57:32 | oeisdata/seq/A002/A002227.seq | f707b711b6079d59ef5d57c4ee76b795 |
A002228 | Smallest prime p such that first n primes (p_1=2, ..., p_n) are 11th power residues mod p. | [
"331",
"39139",
"253243",
"4397207",
"21587171",
"781712537",
"781712537",
"25467966877",
"1304374210679",
"4331892405391"
] | [
"nonn",
"more"
] | 25 | 0 | 5 | [
"A002223",
"A002227",
"A002228",
"A060363",
"A060364"
] | [
"M5438",
"N2364"
] | N. J. A. Sloane | 2024-04-15T04:55:50 | oeisdata/seq/A002/A002228.seq | 58b363c7719b6d75557175408fc0a4e1 |
A002229 | Primitive roots that go with the primes in A002230. | [
"1",
"2",
"3",
"5",
"6",
"7",
"19",
"21",
"23",
"31",
"37",
"38",
"44",
"69",
"73",
"94",
"97",
"101",
"107",
"111",
"113",
"127",
"137",
"151",
"164",
"179",
"194",
"197",
"227",
"229",
"263",
"281",
"293",
"335",
"347",
"359",
"401",
"417"
] | [
"nonn",
"more"
] | 40 | 0 | 5 | [
"A002229",
"A002230"
] | [
"M0620",
"N0226"
] | N. J. A. Sloane | 2023-02-13T11:16:12 | oeisdata/seq/A002/A002229.seq | b03fa64e6d89ee38a5e95856d9a0dad5 |
A002230 | Primes with record values of the least positive primitive root. | [
"2",
"3",
"7",
"23",
"41",
"71",
"191",
"409",
"2161",
"5881",
"36721",
"55441",
"71761",
"110881",
"760321",
"5109721",
"17551561",
"29418841",
"33358081",
"45024841",
"90441961",
"184254841",
"324013369",
"831143041",
"1685283601",
"6064561441",
"7111268641",
"9470788801",
"28725635761",
"108709927561",
"386681163961",
"1990614824641",
"44384069747161",
"89637484042681"
] | [
"nonn",
"easy",
"nice"
] | 50 | 0 | 5 | [
"A002229",
"A002230",
"A023048",
"A114885"
] | [
"M0855",
"N0325"
] | N. J. A. Sloane | 2023-02-13T12:11:34 | oeisdata/seq/A002/A002230.seq | ef1755f2f3d29f948cfdfa6242bbd14e |
A002231 | Primitive roots that go with the primes in A029932. | [
"2",
"3",
"5",
"7",
"11",
"19",
"43",
"53",
"79",
"107",
"149",
"151",
"163",
"211",
"223",
"263",
"277",
"307",
"347",
"349",
"367",
"383",
"461",
"479",
"503"
] | [
"nonn",
"nice",
"more"
] | 31 | 0 | 5 | [
"A002231",
"A029932"
] | [
"M0668",
"N0246"
] | N. J. A. Sloane | 2018-08-04T02:54:36 | oeisdata/seq/A002/A002231.seq | 02e122617b9493d49bf6c880c5250411 |
A002232 | 8th powers written backwards. | [
"0",
"1",
"652",
"1656",
"63556",
"526093",
"6169761",
"1084675",
"61277761",
"12764034",
"1",
"188853412",
"696189924",
"127037518",
"6509875741",
"5260982652",
"6927694924",
"1447575796",
"67506991011",
"14036538961",
"652",
"16395822873",
"63537857845",
"18258901387",
"671413570011",
"526098785251"
] | [
"nonn",
"base"
] | 13 | 0 | 5 | null | null | N. J. A. Sloane | 2023-10-14T16:32:02 | oeisdata/seq/A002/A002232.seq | 61c60b0130c80a17e2759c5709943bdf |
A002233 | a(1) = 1; for n > 1, a(n) = least positive prime primitive root of n-th prime. | [
"1",
"2",
"2",
"3",
"2",
"2",
"3",
"2",
"5",
"2",
"3",
"2",
"7",
"3",
"5",
"2",
"2",
"2",
"2",
"7",
"5",
"3",
"2",
"3",
"5",
"2",
"5",
"2",
"11",
"3",
"3",
"2",
"3",
"2",
"2",
"7",
"5",
"2",
"5",
"2",
"2",
"2",
"19",
"5",
"2",
"3",
"2",
"3",
"2",
"7",
"3",
"7",
"7",
"11",
"3",
"5",
"2",
"43",
"5",
"3",
"3",
"2",
"5",
"17",
"17",
"2",
"3",
"19",
"2",
"2",
"3",
"7",
"11",
"2",
"2",
"5",
"2",
"5",
"3",
"29",
"2",
"2",
"7",
"5",
"17",
"2",
"3",
"13",
"2",
"3",
"2",
"13",
"3",
"2",
"7",
"5",
"2",
"3",
"2",
"2",
"2"
] | [
"nonn",
"nice",
"easy"
] | 68 | 0 | 5 | [
"A001918",
"A002233",
"A122028",
"A223942"
] | [
"M0243",
"N0084"
] | N. J. A. Sloane | 2017-11-20T03:28:48 | oeisdata/seq/A002/A002233.seq | cbbba9b0ac1a4aa0311d743b7b9426ab |
A002234 | Numbers k such that the Woodall number k*2^k - 1 is prime. | [
"2",
"3",
"6",
"30",
"75",
"81",
"115",
"123",
"249",
"362",
"384",
"462",
"512",
"751",
"822",
"5312",
"7755",
"9531",
"12379",
"15822",
"18885",
"22971",
"23005",
"98726",
"143018",
"151023",
"667071",
"1195203",
"1268979",
"1467763",
"2013992",
"2367906",
"3752948",
"17016602"
] | [
"nonn",
"nice",
"hard"
] | 69 | 0 | 5 | [
"A002234",
"A003261",
"A005849",
"A050918"
] | [
"M0820",
"N0311"
] | N. J. A. Sloane, Simon Plouffe | 2025-02-16T08:32:25 | oeisdata/seq/A002/A002234.seq | 5db8a8f7ba1b3dc1471ddc3386cdf8ca |
A002235 | Numbers m such that 3*2^m - 1 is prime. | [
"0",
"1",
"2",
"3",
"4",
"6",
"7",
"11",
"18",
"34",
"38",
"43",
"55",
"64",
"76",
"94",
"103",
"143",
"206",
"216",
"306",
"324",
"391",
"458",
"470",
"827",
"1274",
"3276",
"4204",
"5134",
"7559",
"12676",
"14898",
"18123",
"18819",
"25690",
"26459",
"41628",
"51387",
"71783",
"80330",
"85687",
"88171",
"97063",
"123630",
"155930",
"164987",
"234760"
] | [
"nonn",
"nice"
] | 101 | 0 | 5 | [
"A000043",
"A001771",
"A002235",
"A003307",
"A005541",
"A007505",
"A046865",
"A046866",
"A046867",
"A056725",
"A079906",
"A079907"
] | [
"M0545",
"N0195"
] | N. J. A. Sloane | 2025-02-16T08:32:25 | oeisdata/seq/A002/A002235.seq | 928af22436c6ab8f480de341281eea86 |
A002236 | Numbers k such that 9*2^k - 1 is prime. | [
"1",
"3",
"7",
"13",
"15",
"21",
"43",
"63",
"99",
"109",
"159",
"211",
"309",
"343",
"415",
"469",
"781",
"871",
"939",
"1551",
"3115",
"3349",
"5589",
"5815",
"5893",
"7939",
"8007",
"11547",
"12495",
"22555",
"23647",
"35647",
"83415",
"103059",
"184999",
"275859",
"384243",
"484975",
"503893",
"828709",
"1010277",
"1419855",
"1481821"
] | [
"hard",
"nonn",
"nice"
] | 48 | 0 | 5 | [
"A002236",
"A050524"
] | [
"M2634",
"N1045"
] | N. J. A. Sloane | 2023-06-24T07:48:09 | oeisdata/seq/A002/A002236.seq | e989222cdae12e5f477a820f9fa3737c |
A002237 | Numbers k such that 15*2^k - 1 is prime. | [
"1",
"2",
"4",
"5",
"10",
"14",
"17",
"31",
"41",
"73",
"80",
"82",
"116",
"125",
"145",
"157",
"172",
"202",
"224",
"266",
"289",
"293",
"463",
"1004",
"1246",
"2066",
"2431",
"2705",
"4622",
"5270",
"7613",
"21727",
"21962",
"40742",
"41054",
"60622",
"83263",
"83669",
"91457",
"103940",
"104177",
"108124",
"115327",
"161453",
"172714",
"454681",
"568780",
"656264",
"712294",
"902474",
"1084010",
"1344313"
] | [
"hard",
"nonn"
] | 45 | 0 | 5 | [
"A002237",
"A002258"
] | [
"M0976",
"N0365"
] | N. J. A. Sloane, Simon Plouffe | 2021-02-12T17:46:42 | oeisdata/seq/A002/A002237.seq | 00d3d85961930ca7b18f1655aa679f1e |
A002238 | Numbers k such that 21*2^k - 1 is prime. | [
"1",
"2",
"3",
"7",
"10",
"13",
"18",
"27",
"37",
"51",
"74",
"157",
"271",
"458",
"530",
"891",
"1723",
"1793",
"1849",
"1986",
"2191",
"2869",
"4993",
"7777",
"11730",
"15313",
"29171",
"35899",
"36227",
"71570",
"199219",
"233914",
"297499",
"332523",
"348547",
"538657",
"986130",
"999599"
] | [
"hard",
"nonn"
] | 38 | 0 | 5 | [
"A002238",
"A032360"
] | [
"M0825",
"N0314"
] | N. J. A. Sloane | 2021-12-24T02:30:20 | oeisdata/seq/A002/A002238.seq | 16193bd192dacc32a0053d714d99d279 |
A002239 | 9th powers written backwards. | [
"0",
"1",
"215",
"38691",
"441262",
"5213591",
"69677001",
"70635304",
"827712431",
"984024783",
"1",
"1967497532",
"2530879515",
"37399440601",
"48764016602",
"57395334483",
"63767491786",
"794678785811",
"863092953891",
"977796786223",
"215",
"185640082497",
"2977129627021",
"3641662511081",
"4220457081462"
] | [
"nonn",
"base",
"look"
] | 15 | 0 | 5 | [
"A001017",
"A002239"
] | null | N. J. A. Sloane | 2023-10-14T16:32:59 | oeisdata/seq/A002/A002239.seq | 9f9b36cc82f3883e5f0bdafc6977a9aa |
A002240 | Numbers k such that 33*2^k - 1 is prime. | [
"2",
"3",
"6",
"8",
"10",
"22",
"35",
"42",
"43",
"46",
"56",
"91",
"102",
"106",
"142",
"190",
"208",
"266",
"330",
"360",
"382",
"462",
"503",
"815",
"1038",
"1651",
"1855",
"1858",
"1992",
"2232",
"4462",
"4726",
"5475",
"6702",
"9710",
"10931",
"11503",
"20552",
"22291",
"26575",
"35931",
"39271",
"51326",
"57695",
"63115",
"67182",
"109848",
"128635",
"136971",
"173110",
"174182",
"373446",
"585400",
"598248",
"674050",
"773030"
] | [
"hard",
"nonn"
] | 28 | 0 | 5 | null | [
"M0752",
"N0284"
] | N. J. A. Sloane | 2021-12-20T20:59:26 | oeisdata/seq/A002/A002240.seq | 89fd088ee34c3bb367066f8b10689ae0 |
A002241 | 10th powers written backwards. | [
"0",
"1",
"4201",
"94095",
"6758401",
"5265679",
"67166406",
"942574282",
"4281473701",
"1044876843",
"1",
"10642473952",
"42246371916",
"948194858731",
"679456452982",
"526093056675",
"6777261159901",
"9440093995102",
"4266227640753",
"1087526601316",
"4201",
"10287908897661",
"42419722995562"
] | [
"nonn",
"base"
] | 11 | 0 | 5 | null | null | N. J. A. Sloane | 2023-10-14T16:33:53 | oeisdata/seq/A002/A002241.seq | 92503fd654bb1e724e0c142c3ab9c613 |
A002242 | Numbers k such that 45*2^k - 1 is prime. | [
"1",
"2",
"3",
"4",
"5",
"6",
"8",
"9",
"14",
"15",
"16",
"22",
"28",
"29",
"36",
"37",
"54",
"59",
"85",
"93",
"117",
"119",
"161",
"189",
"193",
"256",
"308",
"322",
"327",
"411",
"466",
"577",
"591",
"902",
"928",
"946",
"1162",
"1428",
"1708",
"1724",
"2063",
"2922",
"2951",
"3111",
"3402",
"4024",
"4485",
"5859",
"6124",
"8981",
"10628",
"19283",
"23522",
"26591",
"28914",
"33954",
"34743",
"76367",
"103546",
"103912",
"104452",
"125132",
"139883",
"174102",
"249065",
"306394",
"368553",
"528245",
"645542",
"818648"
] | [
"hard",
"nonn"
] | 26 | 0 | 5 | null | [
"M0502",
"N0181"
] | N. J. A. Sloane | 2021-12-20T20:59:18 | oeisdata/seq/A002/A002242.seq | da5f5ed8b80612558b8a15fbc34c3907 |
A002243 | Numbers that are not the sum of 3 distinct triangular numbers. | [
"1",
"2",
"3",
"5",
"6",
"8",
"12",
"15",
"20",
"23",
"33",
"78"
] | [
"fini",
"full",
"nonn"
] | 17 | 0 | 5 | [
"A000217",
"A002243",
"A002244"
] | null | N. J. A. Sloane, Dan Hoey | 2014-11-25T10:54:38 | oeisdata/seq/A002/A002243.seq | 59e23b42ff6c7d645288aa6bb5457e3c |
A002244 | Numbers that are not the sum of 3 distinct nonzero triangular numbers. | [
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"11",
"12",
"13",
"15",
"16",
"18",
"20",
"21",
"23",
"27",
"29",
"33",
"36",
"38",
"48",
"51",
"78",
"111",
"183"
] | [
"fini",
"full",
"nonn"
] | 11 | 0 | 5 | [
"A000217",
"A002243",
"A002244"
] | null | N. J. A. Sloane, Dan Hoey | 2014-06-11T17:22:16 | oeisdata/seq/A002/A002244.seq | 3e4946da376ccb7fc6fd9d598d3959ec |
A002245 | A (4,2)-sequence. | [
"0",
"1",
"4",
"6",
"5",
"3",
"7",
"2"
] | [
"fini",
"full",
"nonn"
] | 7 | 0 | 5 | null | null | N. J. A. Sloane | 2023-10-14T16:34:28 | oeisdata/seq/A002/A002245.seq | 08d6c0da62a975f63d2ca67ed9891600 |
A002246 | a(1) = 3; for n > 1, a(n) = 4*phi(n); given a rational number r = p/q, where q>0, (p,q)=1, define its height to be max{|p|,q}; then a(n) = number of rational numbers of height n. | [
"3",
"4",
"8",
"8",
"16",
"8",
"24",
"16",
"24",
"16",
"40",
"16",
"48",
"24",
"32",
"32",
"64",
"24",
"72",
"32",
"48",
"40",
"88",
"32",
"80",
"48",
"72",
"48",
"112",
"32",
"120",
"64",
"80",
"64",
"96",
"48",
"144",
"72",
"96",
"64",
"160",
"48",
"168",
"80",
"96",
"88",
"184",
"64",
"168",
"80",
"128",
"96",
"208",
"72",
"160",
"96",
"144",
"112",
"232",
"64",
"240",
"120",
"144",
"128",
"192",
"80",
"264"
] | [
"nonn"
] | 11 | 0 | 5 | [
"A000010",
"A002246",
"A097080"
] | null | N. J. A. Sloane, Nov 02 2008 | 2017-12-05T21:19:09 | oeisdata/seq/A002/A002246.seq | 1e9371784ea0b1850cbcd0160539c7db |
A002247 | A (6,2)-sequence. | [
"0",
"6",
"2",
"1",
"10",
"8",
"11",
"7",
"4",
"5",
"9",
"3"
] | [
"fini",
"full",
"nonn"
] | 7 | 0 | 5 | null | null | N. J. A. Sloane | 2023-10-14T16:34:57 | oeisdata/seq/A002/A002247.seq | 931b6dd36e36baff4e0edf1cd9112f25 |
A002248 | Number of points on y^2 + xy = x^3 + x^2 + x over GF(2^n). | [
"2",
"8",
"14",
"16",
"22",
"56",
"142",
"288",
"518",
"968",
"1982",
"4144",
"8374",
"16472",
"32494",
"65088",
"131174",
"263144",
"525086",
"1047376",
"2094358",
"4193912",
"8393806",
"16783200",
"33550022",
"67092488",
"134210174",
"268460656",
"536911222"
] | [
"nonn",
"easy"
] | 30 | 0 | 5 | null | null | N. J. A. Sloane, Iwan Duursma | 2022-09-08T08:44:30 | oeisdata/seq/A002/A002248.seq | edbcfaeca83af375d8c8fe3c6f6a423c |
A002249 | a(n) = a(n-1) - 2*a(n-2) with a(0) = 2, a(1) = 1. | [
"2",
"1",
"-3",
"-5",
"1",
"11",
"9",
"-13",
"-31",
"-5",
"57",
"67",
"-47",
"-181",
"-87",
"275",
"449",
"-101",
"-999",
"-797",
"1201",
"2795",
"393",
"-5197",
"-5983",
"4411",
"16377",
"7555",
"-25199",
"-40309",
"10089",
"90707",
"70529",
"-110885",
"-251943",
"-30173",
"473713",
"534059",
"-413367",
"-1481485"
] | [
"sign",
"easy"
] | 113 | 0 | 5 | [
"A002249",
"A014551",
"A060728",
"A107920"
] | null | N. J. A. Sloane, Iwan Duursma | 2025-02-28T09:39:55 | oeisdata/seq/A002/A002249.seq | baf3e660e2e7b90c872af7e5e63bf05d |
A002250 | a(n) = 4^n - 2*3^n. | [
"-1",
"-2",
"-2",
"10",
"94",
"538",
"2638",
"12010",
"52414",
"222778",
"930478",
"3840010",
"15714334",
"63920218",
"258869518",
"1045044010",
"4208873854",
"16921588858",
"67944635758",
"272553384010",
"1092538058974",
"4377125804698",
"17529423925198",
"70180457820010",
"280910117637694",
"1124205329623738",
"4498515895713838"
] | [
"sign",
"easy"
] | 32 | 0 | 5 | [
"A000244",
"A000302",
"A002250",
"A005061",
"A008776"
] | null | N. J. A. Sloane | 2024-09-15T20:24:48 | oeisdata/seq/A002/A002250.seq | f58e70c2019f94c3a02d390080524bc4 |
A002251 | Start with the nonnegative integers; then swap L(k) and U(k) for all k >= 1, where L = A000201, U = A001950 (lower and upper Wythoff sequences). | [
"0",
"2",
"1",
"5",
"7",
"3",
"10",
"4",
"13",
"15",
"6",
"18",
"20",
"8",
"23",
"9",
"26",
"28",
"11",
"31",
"12",
"34",
"36",
"14",
"39",
"41",
"16",
"44",
"17",
"47",
"49",
"19",
"52",
"54",
"21",
"57",
"22",
"60",
"62",
"24",
"65",
"25",
"68",
"70",
"27",
"73",
"75",
"29",
"78",
"30",
"81",
"83",
"32",
"86",
"33",
"89",
"91",
"35",
"94",
"96",
"37",
"99",
"38",
"102",
"104",
"40",
"107",
"109"
] | [
"nonn",
"easy",
"nice",
"changed"
] | 91 | 0 | 5 | [
"A000201",
"A001950",
"A002251",
"A018219",
"A073869",
"A342297"
] | null | Michael Kleber | 2025-04-17T01:53:49 | oeisdata/seq/A002/A002251.seq | b9268332f58970e615cfb41c717d797a |
A002252 | Order of letters on standard U.S. typewriter keyboard. | [
"17",
"23",
"5",
"18",
"20",
"25",
"21",
"9",
"15",
"16",
"1",
"19",
"4",
"6",
"7",
"8",
"10",
"11",
"12",
"26",
"24",
"3",
"22",
"2",
"14",
"13"
] | [
"nonn",
"fini",
"full"
] | 18 | 0 | 5 | [
"A002252",
"A087622"
] | null | N. J. A. Sloane | 2023-10-14T16:36:13 | oeisdata/seq/A002/A002252.seq | 558b8abdc575572390e23eba2ff5aa67 |
A002253 | Numbers k such that 3*2^k + 1 is prime. | [
"1",
"2",
"5",
"6",
"8",
"12",
"18",
"30",
"36",
"41",
"66",
"189",
"201",
"209",
"276",
"353",
"408",
"438",
"534",
"2208",
"2816",
"3168",
"3189",
"3912",
"20909",
"34350",
"42294",
"42665",
"44685",
"48150",
"54792",
"55182",
"59973",
"80190",
"157169",
"213321",
"303093",
"362765",
"382449",
"709968",
"801978",
"916773",
"1832496",
"2145353"
] | [
"hard",
"nonn"
] | 77 | 0 | 5 | [
"A002253",
"A002254",
"A004119",
"A039687",
"A181565"
] | [
"M1318",
"N0506"
] | N. J. A. Sloane | 2025-02-16T08:32:25 | oeisdata/seq/A002/A002253.seq | a57ab8c2022078d7846d2ff9a57653af |
A002254 | Numbers k such that 5*2^k + 1 is prime. | [
"1",
"3",
"7",
"13",
"15",
"25",
"39",
"55",
"75",
"85",
"127",
"1947",
"3313",
"4687",
"5947",
"13165",
"23473",
"26607",
"125413",
"209787",
"240937",
"819739",
"1282755",
"1320487",
"1777515"
] | [
"hard",
"more",
"nonn"
] | 44 | 0 | 5 | [
"A002254",
"A050526"
] | [
"M2635",
"N1046"
] | N. J. A. Sloane | 2025-02-16T08:32:25 | oeisdata/seq/A002/A002254.seq | 3c28e80174a77f0c2631f234872226ea |
A002255 | Numbers k such that 7*4^k + 1 is prime. | [
"1",
"2",
"3",
"7",
"10",
"13",
"25",
"26",
"46",
"60",
"87",
"90",
"95",
"145",
"160",
"195",
"216",
"308",
"415",
"902",
"1128",
"3307",
"6748",
"7747",
"8348",
"11193",
"27243",
"44033",
"47665",
"103542",
"141517",
"280908",
"402267",
"405615",
"745926",
"1069956",
"1083900",
"1457977",
"1507881",
"1755887"
] | [
"hard",
"nonn"
] | 33 | 0 | 5 | [
"A002255",
"A032353"
] | [
"M0826",
"N0315"
] | N. J. A. Sloane | 2023-07-29T23:14:53 | oeisdata/seq/A002/A002255.seq | 91079fd79c2bf23212c599ee52967784 |
A002256 | Numbers k such that 9*2^k + 1 is prime. | [
"1",
"2",
"3",
"6",
"7",
"11",
"14",
"17",
"33",
"42",
"43",
"63",
"65",
"67",
"81",
"134",
"162",
"206",
"211",
"366",
"663",
"782",
"1305",
"1411",
"1494",
"2297",
"2826",
"3230",
"3354",
"3417",
"3690",
"4842",
"5802",
"6937",
"7967",
"9431",
"13903",
"22603",
"24422",
"39186",
"43963",
"47003",
"49902",
"67943",
"114854",
"127003",
"145247"
] | [
"nonn"
] | 46 | 0 | 5 | [
"A002256",
"A050528"
] | [
"M0751",
"N0283"
] | N. J. A. Sloane | 2025-02-16T08:32:25 | oeisdata/seq/A002/A002256.seq | d420e8bd82303eeacefa24199121f54b |
A002257 | Numbers n such that 13*4^n + 1 is prime. | [
"1",
"4",
"5",
"10",
"14",
"41",
"94",
"154",
"158",
"500",
"14140",
"19004",
"21928",
"44009",
"54629",
"57148",
"260653",
"281228",
"342280",
"519448",
"749938",
"930866"
] | [
"nonn",
"more"
] | 34 | 0 | 5 | [
"A002257",
"A032356"
] | [
"M3247",
"N1310"
] | N. J. A. Sloane | 2022-09-08T08:44:30 | oeisdata/seq/A002/A002257.seq | b9235c00587e27dcdf8f5efff572f2ad |
A002258 | Numbers k such that 15*2^k + 1 is prime. | [
"1",
"2",
"4",
"9",
"10",
"12",
"27",
"37",
"38",
"44",
"48",
"78",
"112",
"168",
"229",
"297",
"339",
"517",
"522",
"654",
"900",
"1518",
"2808",
"2875",
"3128",
"3888",
"4410",
"6804",
"7050",
"7392",
"19219",
"21445",
"21550",
"24105",
"24995",
"34224",
"34260",
"43388",
"48444",
"61758",
"184290",
"294894",
"300488",
"403929",
"483098",
"635989"
] | [
"hard",
"nonn"
] | 51 | 0 | 5 | null | [
"M1165",
"N0445"
] | N. J. A. Sloane | 2024-12-21T09:46:10 | oeisdata/seq/A002/A002258.seq | 0dec7585f3cd00ed95d8fe5aa704ba2e |
A002259 | Numbers k such that 17*2^k + 1 is prime. | [
"3",
"15",
"27",
"51",
"147",
"243",
"267",
"347",
"471",
"747",
"2163",
"3087",
"5355",
"6539",
"7311",
"99231",
"824451",
"1388355",
"1990299",
"8636199"
] | [
"hard",
"more",
"nonn"
] | 38 | 0 | 5 | null | [
"M2985",
"N1206"
] | N. J. A. Sloane | 2024-12-22T09:29:11 | oeisdata/seq/A002/A002259.seq | 8439a0a001c0ed52014939baff9a8118 |
A002260 | Triangle read by rows: T(n,k) = k for n >= 1, k = 1..n. | [
"1",
"1",
"2",
"1",
"2",
"3",
"1",
"2",
"3",
"4",
"1",
"2",
"3",
"4",
"5",
"1",
"2",
"3",
"4",
"5",
"6",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"10",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"10",
"11",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"10",
"11",
"12",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"10",
"11",
"12",
"13",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"10",
"11",
"12",
"13",
"14"
] | [
"nonn",
"easy",
"nice",
"tabl",
"look",
"changed"
] | 222 | 0 | 5 | [
"A000096",
"A000217",
"A000290",
"A000326",
"A000384",
"A001710",
"A001840",
"A001972",
"A002260",
"A002262",
"A002620",
"A003056",
"A004526",
"A004736",
"A025581",
"A051942",
"A055998",
"A055999",
"A056000",
"A056115",
"A056119",
"A056121",
"A056126",
"A056534",
"A094727",
"A101859",
"A108872",
"A127779",
"A132754",
"A132755",
"A132756",
"A132757",
"A132758",
"A140756"
] | null | Angele Hamel (amh(AT)maths.soton.ac.uk) | 2025-04-17T03:37:30 | oeisdata/seq/A002/A002260.seq | 878a1b3dacf12a6ef6434f3dbfcb20f7 |
A002261 | Numbers k such that 11*2^k + 1 is prime. | [
"1",
"3",
"5",
"7",
"19",
"21",
"43",
"81",
"125",
"127",
"209",
"211",
"3225",
"4543",
"10179",
"15329",
"18759",
"28277",
"93279",
"105741",
"268009",
"412447",
"525589",
"644677",
"886071",
"960901",
"1343347",
"2230369",
"2476839",
"2691961",
"2897409",
"3771821",
"8103463"
] | [
"hard",
"nonn"
] | 45 | 0 | 5 | null | [
"M2425",
"N0960"
] | N. J. A. Sloane | 2024-12-22T09:29:16 | oeisdata/seq/A002/A002261.seq | 9f879e450d4a467ce291a14962758b38 |
A002262 | Triangle read by rows: T(n,k) = k, 0 <= k <= n, in which row n lists the first n+1 nonnegative integers. | [
"0",
"0",
"1",
"0",
"1",
"2",
"0",
"1",
"2",
"3",
"0",
"1",
"2",
"3",
"4",
"0",
"1",
"2",
"3",
"4",
"5",
"0",
"1",
"2",
"3",
"4",
"5",
"6",
"0",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"0",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"0",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"0",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"10",
"0",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"10",
"11",
"0",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"10",
"11",
"12",
"0",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"10",
"11",
"12",
"13"
] | [
"nonn",
"tabl",
"easy",
"nice"
] | 158 | 0 | 5 | [
"A002024",
"A002260",
"A002262",
"A004736",
"A025581",
"A025675",
"A025682",
"A025691",
"A048151",
"A048645",
"A053186",
"A053645",
"A056558",
"A060510",
"A127324"
] | null | Angele Hamel (amh(AT)maths.soton.ac.uk) | 2024-09-29T23:46:23 | oeisdata/seq/A002/A002262.seq | 658a52e7d8761c06c800b16fdcbb5c3a |
A002263 | Numbers k such that 25*4^k + 1 is prime. | [
"1",
"2",
"3",
"5",
"10",
"11",
"26",
"32",
"39",
"92",
"116",
"134",
"170",
"224",
"277",
"332",
"370",
"374",
"640",
"664",
"820",
"1657",
"1952",
"1969",
"2576"
] | [
"nonn"
] | 31 | 0 | 5 | [
"A002263",
"A032362"
] | [
"M0721",
"N0269"
] | N. J. A. Sloane | 2022-09-08T08:44:30 | oeisdata/seq/A002/A002263.seq | 1b6e2a7f6ffc0326b94a7bd206b8aa41 |
A002264 | Nonnegative integers repeated 3 times. | [
"0",
"0",
"0",
"1",
"1",
"1",
"2",
"2",
"2",
"3",
"3",
"3",
"4",
"4",
"4",
"5",
"5",
"5",
"6",
"6",
"6",
"7",
"7",
"7",
"8",
"8",
"8",
"9",
"9",
"9",
"10",
"10",
"10",
"11",
"11",
"11",
"12",
"12",
"12",
"13",
"13",
"13",
"14",
"14",
"14",
"15",
"15",
"15",
"16",
"16",
"16",
"17",
"17",
"17",
"18",
"18",
"18",
"19",
"19",
"19",
"20",
"20",
"20",
"21",
"21",
"21",
"22",
"22",
"22",
"23",
"23",
"23",
"24",
"24",
"24",
"25"
] | [
"nonn",
"easy"
] | 146 | 0 | 5 | [
"A001477",
"A002264",
"A002265",
"A002266",
"A004396",
"A004523",
"A004526",
"A008615",
"A008620",
"A010761",
"A010762",
"A010872",
"A010873",
"A010874",
"A022003",
"A110532",
"A110533",
"A130518",
"A137221",
"A235791"
] | null | N. J. A. Sloane | 2025-03-28T17:31:53 | oeisdata/seq/A002/A002264.seq | 31dcfc768df365dfcc2b9a77318decf4 |
A002265 | Nonnegative integers repeated 4 times. | [
"0",
"0",
"0",
"0",
"1",
"1",
"1",
"1",
"2",
"2",
"2",
"2",
"3",
"3",
"3",
"3",
"4",
"4",
"4",
"4",
"5",
"5",
"5",
"5",
"6",
"6",
"6",
"6",
"7",
"7",
"7",
"7",
"8",
"8",
"8",
"8",
"9",
"9",
"9",
"9",
"10",
"10",
"10",
"10",
"11",
"11",
"11",
"11",
"12",
"12",
"12",
"12",
"13",
"13",
"13",
"13",
"14",
"14",
"14",
"14",
"15",
"15",
"15",
"15",
"16",
"16",
"16",
"16",
"17",
"17",
"17",
"17",
"18",
"18",
"18",
"18",
"19",
"19",
"19",
"19"
] | [
"nonn",
"easy"
] | 142 | 0 | 5 | [
"A002265",
"A004526",
"A008615",
"A008621",
"A010872",
"A010873",
"A010874",
"A011765",
"A130519",
"A180969",
"A249356"
] | null | N. J. A. Sloane | 2023-12-30T10:56:11 | oeisdata/seq/A002/A002265.seq | 3aed9195f62747e3ab2f4376362350c5 |
A002266 | Integers repeated 5 times. | [
"0",
"0",
"0",
"0",
"0",
"1",
"1",
"1",
"1",
"1",
"2",
"2",
"2",
"2",
"2",
"3",
"3",
"3",
"3",
"3",
"4",
"4",
"4",
"4",
"4",
"5",
"5",
"5",
"5",
"5",
"6",
"6",
"6",
"6",
"6",
"7",
"7",
"7",
"7",
"7",
"8",
"8",
"8",
"8",
"8",
"9",
"9",
"9",
"9",
"9",
"10",
"10",
"10",
"10",
"10",
"11",
"11",
"11",
"11",
"11",
"12",
"12",
"12",
"12",
"12",
"13",
"13",
"13",
"13",
"13",
"14",
"14",
"14",
"14",
"14",
"15",
"15",
"15",
"15",
"15",
"16",
"16",
"16"
] | [
"nonn",
"easy"
] | 71 | 0 | 5 | [
"A002162",
"A002264",
"A002265",
"A002266",
"A004526",
"A008648",
"A010761",
"A010762",
"A010766",
"A010872",
"A010873",
"A010874",
"A110532",
"A110533",
"A130520"
] | null | N. J. A. Sloane | 2023-12-14T05:57:53 | oeisdata/seq/A002/A002266.seq | 9fea6ff14584c7a0aa3c920053fd71a8 |
A002267 | The 15 supersingular primes: primes dividing order of Monster simple group. | [
"2",
"3",
"5",
"7",
"11",
"13",
"17",
"19",
"23",
"29",
"31",
"41",
"47",
"59",
"71"
] | [
"nonn",
"fini",
"full",
"nice"
] | 60 | 0 | 5 | [
"A001379",
"A002267",
"A003131",
"A051161",
"A109611"
] | null | N. J. A. Sloane | 2025-02-17T16:23:02 | oeisdata/seq/A002/A002267.seq | 342fdb8c9263dcaa526648ea4b0f6cd1 |
A002268 | Dimensions of integral lattices that are irreducible modulo every prime (there may be missing terms!). | [
"1",
"8",
"24",
"248"
] | [
"nonn",
"nice"
] | 13 | 0 | 5 | null | null | N. J. A. Sloane and J. H. Conway | 2013-11-06T10:42:15 | oeisdata/seq/A002/A002268.seq | 58408f48f3f73d16657434b45d254a93 |
A002269 | Numbers k such that 39*2^k + 1 is prime. | [
"1",
"2",
"3",
"5",
"7",
"10",
"11",
"13",
"14",
"18",
"21",
"22",
"31",
"42",
"67",
"70",
"71",
"73",
"251",
"370",
"375",
"389",
"407",
"518",
"818",
"865",
"1057",
"1602",
"2211",
"3049",
"4802",
"4865",
"5317",
"7583",
"8061",
"9853",
"10217",
"12103",
"13721",
"14927",
"15441",
"15931",
"16709",
"18907",
"20221",
"21882",
"25654",
"28437",
"30325"
] | [
"hard",
"nonn"
] | 57 | 0 | 5 | null | [
"M0640",
"N0234"
] | N. J. A. Sloane | 2024-12-22T09:15:39 | oeisdata/seq/A002/A002269.seq | a7c9e00635f2b20e5aed435127c50a7d |
A002270 | Composite numbers k such that k*sigma(k) == 2 (mod phi(k)). | [
"4",
"6",
"22"
] | [
"nonn",
"fini",
"full",
"bref"
] | 20 | 0 | 5 | [
"A002270",
"A051948"
] | null | N. J. A. Sloane | 2023-10-14T21:10:17 | oeisdata/seq/A002/A002270.seq | 5484bf25681f26743c16ad07ec560759 |
A002271 | Numbers m such that all odd numbers k, 1 < k < m, relatively prime to m are primes. | [
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"12",
"15",
"18",
"21",
"24",
"30",
"45",
"105"
] | [
"nonn",
"fini",
"full"
] | 10 | 0 | 5 | null | null | N. J. A. Sloane | 2023-10-14T21:10:09 | oeisdata/seq/A002/A002271.seq | c544a6c6ec332b217772cd7fb7fef044 |
A002272 | Theta series of 32-dimensional Quebbemann lattice Q_32. | [
"1",
"0",
"0",
"261120",
"18947520",
"535818240",
"8320327680",
"83347937280",
"622558664640",
"3614759362560",
"17694184734720",
"73337844372480",
"272615629589760",
"898646461378560",
"2752654757806080",
"7687895624386560"
] | [
"nonn"
] | 23 | 0 | 5 | null | null | N. J. A. Sloane | 2023-10-14T23:48:41 | oeisdata/seq/A002/A002272.seq | de3709f519bc206534a6fd4567c4e287 |
A002273 | Theta series of 28-dimensional Quebbemann lattice. | [
"1",
"0",
"98280",
"19138560",
"805208040",
"14651449344",
"156717687840",
"1162883174400",
"6596666916840",
"30507984568320",
"119992701299184",
"414348381296640",
"1283840894706720",
"3635166831206400",
"9523995863722560"
] | [
"nonn",
"nice",
"easy"
] | 14 | 0 | 5 | null | null | N. J. A. Sloane | 2022-01-29T01:09:21 | oeisdata/seq/A002/A002273.seq | 8126346c991c1002de7c6a9ccd04e16d |
A002274 | Numbers k such that 57*2^k + 1 is prime. | [
"2",
"3",
"7",
"8",
"10",
"16",
"18",
"19",
"40",
"48",
"55",
"90",
"96",
"98",
"190",
"398",
"456",
"502",
"719",
"1312",
"1399",
"1828",
"6723",
"6816",
"10680",
"12592",
"20742",
"25010",
"26838",
"29623",
"45435",
"52783",
"70950",
"89691",
"111691",
"114400",
"136152",
"145183",
"146223",
"177459",
"212908",
"300910",
"342151",
"360447",
"382156",
"411635",
"442948",
"519862",
"519892",
"975036",
"1158942",
"1181438",
"1756702",
"2033643"
] | [
"hard",
"nonn"
] | 41 | 0 | 5 | null | [
"M0822",
"N0313"
] | N. J. A. Sloane | 2023-10-15T00:00:14 | oeisdata/seq/A002/A002274.seq | 23a1cc14efce324bb34874b3f111808f |
A002275 | Repunits: (10^n - 1)/9. Often denoted by R_n. | [
"0",
"1",
"11",
"111",
"1111",
"11111",
"111111",
"1111111",
"11111111",
"111111111",
"1111111111",
"11111111111",
"111111111111",
"1111111111111",
"11111111111111",
"111111111111111",
"1111111111111111",
"11111111111111111",
"111111111111111111",
"1111111111111111111",
"11111111111111111111"
] | [
"easy",
"nonn",
"nice",
"core"
] | 291 | 0 | 5 | [
"A000042",
"A002275",
"A002276",
"A002277",
"A002278",
"A002279",
"A002280",
"A002281",
"A002282",
"A003020",
"A004023",
"A011557",
"A034048",
"A034049",
"A034050",
"A034051",
"A034052",
"A034053",
"A034054",
"A034055",
"A034056",
"A046053",
"A059988",
"A065444",
"A067063",
"A075415",
"A083278",
"A095370",
"A099814",
"A100706",
"A102380",
"A125134",
"A178635",
"A204845",
"A204846",
"A204847",
"A204848",
"A206244"
] | null | N. J. A. Sloane | 2025-03-14T15:04:22 | oeisdata/seq/A002/A002275.seq | 56c22ce528fccb20a335485d7f9a15de |
A002276 | a(n) = 2*(10^n - 1)/9. | [
"0",
"2",
"22",
"222",
"2222",
"22222",
"222222",
"2222222",
"22222222",
"222222222",
"2222222222",
"22222222222",
"222222222222",
"2222222222222",
"22222222222222",
"222222222222222",
"2222222222222222",
"22222222222222222",
"222222222222222222",
"2222222222222222222"
] | [
"nonn",
"easy"
] | 50 | 0 | 5 | [
"A002275",
"A002276",
"A002277",
"A002278",
"A002279",
"A002280",
"A002281",
"A002282",
"A178634"
] | null | N. J. A. Sloane | 2024-02-08T07:10:05 | oeisdata/seq/A002/A002276.seq | 88e9556e7d10208f2dfa1491b0ccc1b9 |
A002277 | a(n) = 3*(10^n - 1)/9. | [
"0",
"3",
"33",
"333",
"3333",
"33333",
"333333",
"3333333",
"33333333",
"333333333",
"3333333333",
"33333333333",
"333333333333",
"3333333333333",
"33333333333333",
"333333333333333",
"3333333333333333",
"33333333333333333",
"333333333333333333",
"3333333333333333333",
"33333333333333333333",
"333333333333333333333"
] | [
"easy",
"nonn"
] | 84 | 0 | 5 | [
"A002275",
"A002276",
"A002277",
"A002278",
"A002279",
"A002280",
"A002281",
"A002282",
"A002283",
"A005188",
"A067275",
"A075412",
"A093143",
"A135702",
"A178631",
"A178633",
"A246057",
"A281857",
"A281858",
"A281860"
] | null | N. J. A. Sloane | 2025-02-16T08:32:25 | oeisdata/seq/A002/A002277.seq | f9b85bb1218e995206b13efb64075d40 |
A002278 | a(n) = 4*(10^n - 1)/9. | [
"0",
"4",
"44",
"444",
"4444",
"44444",
"444444",
"4444444",
"44444444",
"444444444",
"4444444444",
"44444444444",
"444444444444",
"4444444444444",
"44444444444444",
"444444444444444",
"4444444444444444",
"44444444444444444",
"444444444444444444",
"4444444444444444444",
"44444444444444444444",
"444444444444444444444"
] | [
"easy",
"nonn"
] | 46 | 0 | 5 | [
"A002275",
"A002276",
"A002277",
"A002278",
"A002279",
"A002280",
"A002281",
"A002282",
"A002283",
"A007091",
"A024049",
"A075415",
"A178632"
] | null | N. J. A. Sloane | 2024-06-16T06:16:08 | oeisdata/seq/A002/A002278.seq | 489c75743fa87b6ecf4b5e86faf0a34b |
A002279 | a(n) = 5*(10^n - 1)/9. | [
"0",
"5",
"55",
"555",
"5555",
"55555",
"555555",
"5555555",
"55555555",
"555555555",
"5555555555",
"55555555555",
"555555555555",
"5555555555555",
"55555555555555",
"555555555555555",
"5555555555555555",
"55555555555555555",
"555555555555555555",
"5555555555555555555",
"55555555555555555555",
"555555555555555555555"
] | [
"easy",
"nonn"
] | 68 | 0 | 5 | [
"A002275",
"A002276",
"A002277",
"A002278",
"A002279",
"A002280",
"A002281",
"A002282",
"A002283",
"A010785",
"A075415",
"A178632"
] | null | N. J. A. Sloane | 2025-02-16T08:32:25 | oeisdata/seq/A002/A002279.seq | 8e411ff03d184ea7c5861305ee66a4ab |
A002280 | a(n) = 6*(10^n - 1)/9. | [
"0",
"6",
"66",
"666",
"6666",
"66666",
"666666",
"6666666",
"66666666",
"666666666",
"6666666666",
"66666666666",
"666666666666",
"6666666666666",
"66666666666666",
"666666666666666",
"6666666666666666",
"66666666666666666",
"666666666666666666",
"6666666666666666666",
"66666666666666666666",
"666666666666666666666"
] | [
"easy",
"nonn"
] | 48 | 0 | 5 | [
"A002275",
"A002276",
"A002277",
"A002278",
"A002279",
"A002280",
"A002281",
"A002282",
"A072912",
"A073548",
"A075415",
"A178631",
"A178633"
] | null | N. J. A. Sloane | 2024-02-08T07:10:16 | oeisdata/seq/A002/A002280.seq | 3944c3a5ac4003ab22754164f44a06f4 |
A002281 | a(n) = 7*(10^n - 1)/9. | [
"0",
"7",
"77",
"777",
"7777",
"77777",
"777777",
"7777777",
"77777777",
"777777777",
"7777777777",
"77777777777",
"777777777777",
"7777777777777",
"77777777777777",
"777777777777777",
"7777777777777777",
"77777777777777777",
"777777777777777777",
"7777777777777777777",
"77777777777777777777",
"777777777777777777777"
] | [
"easy",
"nonn"
] | 50 | 0 | 5 | [
"A002275",
"A002276",
"A002277",
"A002278",
"A002279",
"A002280",
"A002281",
"A002282",
"A178630",
"A178634"
] | null | N. J. A. Sloane | 2024-02-08T07:10:19 | oeisdata/seq/A002/A002281.seq | 5d5479a46accf922f3874c16ce4e815b |
A002282 | a(n) = 8*(10^n - 1)/9. | [
"0",
"8",
"88",
"888",
"8888",
"88888",
"888888",
"8888888",
"88888888",
"888888888",
"8888888888",
"88888888888",
"888888888888",
"8888888888888",
"88888888888888",
"888888888888888",
"8888888888888888",
"88888888888888888",
"888888888888888888",
"8888888888888888888"
] | [
"easy",
"nonn"
] | 53 | 0 | 5 | [
"A002275",
"A002276",
"A002277",
"A002278",
"A002279",
"A002280",
"A002281",
"A002282",
"A051003",
"A059482",
"A059988",
"A075412"
] | null | N. J. A. Sloane | 2024-02-08T07:10:38 | oeisdata/seq/A002/A002282.seq | 0b9be7a006203dcbd3173d9c177ce225 |
A002283 | a(n) = 10^n - 1. | [
"0",
"9",
"99",
"999",
"9999",
"99999",
"999999",
"9999999",
"99999999",
"999999999",
"9999999999",
"99999999999",
"999999999999",
"9999999999999",
"99999999999999",
"999999999999999",
"9999999999999999",
"99999999999999999",
"999999999999999999",
"9999999999999999999",
"99999999999999999999",
"999999999999999999999",
"9999999999999999999999"
] | [
"nonn",
"easy"
] | 133 | 0 | 5 | [
"A000533",
"A002275",
"A002276",
"A002277",
"A002278",
"A002279",
"A002280",
"A002281",
"A002282",
"A002283",
"A003020",
"A007138",
"A007953",
"A008591",
"A010888",
"A048379",
"A066138",
"A073668",
"A075412",
"A075415",
"A168624",
"A178631",
"A178632",
"A178633",
"A178634",
"A178635",
"A276352"
] | null | N. J. A. Sloane | 2024-02-07T01:13:47 | oeisdata/seq/A002/A002283.seq | 329987758b7f44550c61a163013ebe3f |
A002284 | q-expansion of modular form of weight 13/2: eta(8 tau)^12 * theta(tau). | [
"0",
"0",
"0",
"0",
"1",
"2",
"0",
"0",
"2",
"0",
"0",
"0",
"-12",
"-22",
"0",
"0",
"-24",
"0",
"0",
"0",
"56",
"84",
"0",
"0",
"108",
"0",
"0",
"0",
"-112",
"-66",
"0",
"0",
"-176",
"0",
"0",
"0",
"9",
"-398",
"0",
"0",
"-196",
"0",
"0",
"0",
"364",
"990",
"0",
"0",
"1056",
"0",
"0",
"0",
"-616",
"70",
"0",
"0",
"-728",
"0",
"0",
"0",
"432",
"-2354",
"0",
"0",
"-1472",
"0",
"0",
"0",
"-240",
"1080",
"0",
"0",
"990",
"0",
"0",
"0"
] | [
"sign",
"nice"
] | 21 | 0 | 5 | null | null | N. J. A. Sloane | 2015-11-24T03:39:07 | oeisdata/seq/A002/A002284.seq | f1b7619fd729973f569a3fae1610ea64 |
A002285 | Decimal expansion of common logarithm of e. | [
"4",
"3",
"4",
"2",
"9",
"4",
"4",
"8",
"1",
"9",
"0",
"3",
"2",
"5",
"1",
"8",
"2",
"7",
"6",
"5",
"1",
"1",
"2",
"8",
"9",
"1",
"8",
"9",
"1",
"6",
"6",
"0",
"5",
"0",
"8",
"2",
"2",
"9",
"4",
"3",
"9",
"7",
"0",
"0",
"5",
"8",
"0",
"3",
"6",
"6",
"6",
"5",
"6",
"6",
"1",
"1",
"4",
"4",
"5",
"3",
"7",
"8",
"3",
"1",
"6",
"5",
"8",
"6",
"4",
"6",
"4",
"9",
"2",
"0",
"8",
"8",
"7",
"0",
"7",
"7",
"4",
"7",
"2",
"9",
"2",
"2",
"4",
"9",
"4",
"9",
"3",
"3",
"8",
"4",
"3",
"1",
"7",
"4",
"8",
"3",
"1",
"8",
"7",
"0",
"6"
] | [
"nonn",
"cons"
] | 91 | 0 | 5 | [
"A001008",
"A002285",
"A002392",
"A002805",
"A114467",
"A114468"
] | [
"M3210",
"N1299"
] | N. J. A. Sloane | 2025-02-16T08:32:25 | oeisdata/seq/A002/A002285.seq | 7415a81dfb04123165bc440f5ef95221 |
A002286 | Bisection of A002470. | [
"1",
"-8",
"10",
"80",
"-231",
"-248",
"1466",
"-80",
"-4766",
"1944",
"9600",
"-2704",
"-15525",
"-3984",
"25498",
"10816",
"-29760",
"800",
"1994",
"-11728",
"29362",
"-5560",
"-2310",
"-1952",
"21649",
"38128",
"-192854",
"-2480",
"233280",
"-20248",
"-10918",
"-18480",
"14660",
"-101768",
"-324480",
"137424"
] | [
"sign"
] | 20 | 0 | 5 | [
"A002286",
"A002287",
"A002470"
] | [
"M4479",
"N1896"
] | N. J. A. Sloane | 2023-12-26T23:22:00 | oeisdata/seq/A002/A002286.seq | 30d7a9b272d63065eba1b3e4060d8ed1 |
A002287 | Bisection of A002470. | [
"0",
"4",
"-48",
"224",
"-448",
"40",
"1408",
"-2240",
"1280",
"-924",
"-480",
"6944",
"-8704",
"5864",
"-14080",
"2240",
"33792",
"-19064",
"11088",
"-54432",
"-4480",
"38400",
"43648",
"75712",
"-124928",
"-62100",
"-70368",
"111552",
"87040",
"101992",
"14080",
"-302848",
"53248",
"-119040",
"228768",
"-22400"
] | [
"sign",
"more"
] | 19 | 0 | 5 | [
"A002286",
"A002287",
"A002470"
] | [
"M3685",
"N1504"
] | N. J. A. Sloane | 2023-12-26T23:27:13 | oeisdata/seq/A002/A002287.seq | 71972ed3eb32fff246297cc43fe4520c |
A002288 | G.f.: q * Product_{m>=1} (1-q^m)^8*(1-q^2m)^8. | [
"0",
"1",
"-8",
"12",
"64",
"-210",
"-96",
"1016",
"-512",
"-2043",
"1680",
"1092",
"768",
"1382",
"-8128",
"-2520",
"4096",
"14706",
"16344",
"-39940",
"-13440",
"12192",
"-8736",
"68712",
"-6144",
"-34025",
"-11056",
"-50760",
"65024",
"-102570",
"20160",
"227552",
"-32768",
"13104",
"-117648",
"-213360",
"-130752",
"160526",
"319520"
] | [
"sign",
"easy",
"nice",
"mult"
] | 83 | 0 | 5 | [
"A002288",
"A030211"
] | [
"M4483",
"N1898"
] | N. J. A. Sloane | 2025-03-28T16:45:40 | oeisdata/seq/A002/A002288.seq | 7a5b6e4b8f64fd5e60bbb7d865544b73 |
A002289 | Weight distribution of [ 23,12,7 ] binary perfect Golay code. | [
"1",
"0",
"0",
"0",
"0",
"0",
"0",
"253",
"506",
"0",
"0",
"1288",
"1288",
"0",
"0",
"506",
"253",
"0",
"0",
"0",
"0",
"0",
"0",
"1"
] | [
"nonn",
"fini",
"full",
"nice"
] | 16 | 0 | 5 | [
"A001380",
"A002289"
] | null | N. J. A. Sloane | 2022-01-29T12:17:02 | oeisdata/seq/A002/A002289.seq | c087eabbd00ea612d1b0997a20d2d688 |
A002290 | Absolute value of Glaisher's alpha(n). | [
"1",
"4",
"10",
"56",
"29",
"332",
"30",
"1064",
"302",
"1940",
"288",
"1960",
"1071",
"1192",
"1938",
"736",
"2000",
"1488",
"5014",
"7288",
"4170",
"10644",
"8482",
"11184",
"12647",
"15544",
"15590",
"9992",
"25424",
"4604",
"26610",
"2472",
"28972",
"3140",
"26464",
"39416",
"31338",
"24764",
"25248",
"16176",
"48871",
"67540",
"60364",
"29256",
"50874",
"12656"
] | [
"nonn"
] | 37 | 0 | 5 | [
"A002290",
"A225543"
] | [
"M3403",
"N1376"
] | N. J. A. Sloane | 2023-10-14T23:52:18 | oeisdata/seq/A002/A002290.seq | 903fb981cbb79c789867e35dea93bc21 |
A002291 | Absolute value of Glaisher's beta'(2n+1). | [
"0",
"1",
"4",
"2",
"8",
"13",
"28",
"26",
"56",
"69",
"48",
"134",
"80",
"182",
"84",
"312",
"280",
"204",
"332",
"142",
"816",
"91",
"196",
"780",
"224",
"526",
"244",
"1198",
"2216",
"767",
"508",
"390",
"400",
"1167",
"1424",
"466",
"2264",
"1391",
"1392",
"3796",
"1480",
"11",
"1768",
"2274",
"1320",
"1508",
"1984",
"8450"
] | [
"nonn"
] | 19 | 0 | 5 | [
"A002291",
"A225872",
"A322032"
] | [
"M3205",
"N1297"
] | N. J. A. Sloane | 2023-10-14T23:52:54 | oeisdata/seq/A002/A002291.seq | 88284207bf91a80e87b57c7b79b798a5 |
A002292 | Related to representation as sums of squares. | [
"1",
"20",
"74",
"24",
"157",
"124",
"478",
"1480",
"1198",
"3044",
"480",
"184",
"2351",
"1720",
"3282",
"5728",
"2480",
"1776",
"10326",
"9560",
"8886",
"9188",
"11618",
"23664",
"16231",
"23960",
"11686",
"9176",
"60880",
"16876",
"18482",
"3768",
"35372",
"15532",
"3680",
"31960",
"4886",
"47020",
"2976",
"44560"
] | [
"nonn"
] | 23 | 0 | 5 | [
"A002292",
"A225923"
] | [
"M5085",
"N2201"
] | N. J. A. Sloane | 2021-02-14T02:16:15 | oeisdata/seq/A002/A002292.seq | 1ad8ad23dd75c71cc017db95f0664569 |
A002293 | Number of dissections of a polygon: binomial(4*n, n)/(3*n + 1). | [
"1",
"1",
"4",
"22",
"140",
"969",
"7084",
"53820",
"420732",
"3362260",
"27343888",
"225568798",
"1882933364",
"15875338990",
"134993766600",
"1156393243320",
"9969937491420",
"86445222719724",
"753310723010608",
"6594154339031800",
"57956002331347120",
"511238042454541545"
] | [
"nonn",
"nice",
"easy",
"changed"
] | 461 | 0 | 5 | [
"A000260",
"A001764",
"A002293",
"A002294",
"A002295",
"A002296",
"A005038",
"A005040",
"A006632",
"A006633",
"A006634",
"A025174",
"A027836",
"A062993",
"A062994",
"A069271",
"A070914",
"A130564",
"A196678",
"A224274",
"A233658",
"A233666",
"A233667",
"A277877",
"A283049",
"A283101",
"A283102",
"A283103",
"A346646",
"A346664",
"A369471",
"A369472"
] | [
"M3587",
"N1454"
] | N. J. A. Sloane | 2025-04-11T08:45:28 | oeisdata/seq/A002/A002293.seq | 63badf1650cb15cfb1f3d9e83b1365c8 |
A002294 | a(n) = binomial(5*n, n)/(4*n + 1). | [
"1",
"1",
"5",
"35",
"285",
"2530",
"23751",
"231880",
"2330445",
"23950355",
"250543370",
"2658968130",
"28558343775",
"309831575760",
"3390416787880",
"37377257159280",
"414741863546285",
"4628362722856425",
"51912988256282175",
"584909606696793885",
"6617078646960613370"
] | [
"easy",
"nonn",
"nice",
"changed"
] | 225 | 0 | 5 | [
"A001764",
"A002293",
"A002294",
"A002295",
"A002296",
"A004127",
"A062993",
"A130564",
"A143546",
"A221184",
"A258708",
"A346647",
"A346665",
"A369473"
] | [
"M3977",
"N1646"
] | N. J. A. Sloane | 2025-04-11T08:44:10 | oeisdata/seq/A002/A002294.seq | 106f714a477b80e904673f75d09c1781 |
A002295 | Number of dissections of a polygon: binomial(6n,n)/(5n+1). | [
"1",
"1",
"6",
"51",
"506",
"5481",
"62832",
"749398",
"9203634",
"115607310",
"1478314266",
"19180049928",
"251857119696",
"3340843549855",
"44700485049720",
"602574657427116",
"8175951659117794",
"111572030260242090",
"1530312970340384580",
"21085148778264281865",
"291705220704719165526"
] | [
"easy",
"nonn",
"nice"
] | 153 | 0 | 5 | [
"A001764",
"A002293",
"A002294",
"A002295",
"A002296",
"A062993",
"A130564"
] | [
"M4260",
"N1780"
] | N. J. A. Sloane | 2025-01-08T12:55:20 | oeisdata/seq/A002/A002295.seq | 31ca1048ef3ce96067bac8aecc27ae16 |
A002296 | Number of dissections of a polygon: binomial(7n,n)/(6n+1). | [
"1",
"1",
"7",
"70",
"819",
"10472",
"141778",
"1997688",
"28989675",
"430321633",
"6503352856",
"99726673130",
"1547847846090",
"24269405074740",
"383846168712104",
"6116574500860880",
"98106248306858715",
"1582638261961640247",
"25661404527790252375",
"417980115131315136400"
] | [
"easy",
"nonn",
"nice"
] | 123 | 0 | 5 | [
"A001764",
"A002293",
"A002294",
"A002295",
"A002296",
"A062993",
"A130564",
"A235535",
"A235536",
"A258708"
] | [
"M4442",
"N1878"
] | N. J. A. Sloane | 2025-01-08T13:00:28 | oeisdata/seq/A002/A002296.seq | 717999ce4e69ca5bb551d86a0b4513b4 |
A002297 | Numerator of (2/Pi)*Integral_{0..inf} (sin x / x)^n dx. | [
"1",
"1",
"3",
"2",
"115",
"11",
"5887",
"151",
"259723",
"15619",
"381773117",
"655177",
"20646903199",
"27085381",
"467168310097",
"2330931341",
"75920439315929441",
"12157712239",
"5278968781483042969",
"37307713155613",
"9093099984535515162569",
"339781108897078469",
"168702835448329388944396777"
] | [
"nonn",
"frac",
"easy",
"nice"
] | 36 | 0 | 5 | [
"A002297",
"A002298",
"A002304",
"A002305",
"A049330"
] | [
"M2262",
"N0893"
] | N. J. A. Sloane | 2018-01-11T01:09:01 | oeisdata/seq/A002/A002297.seq | d9d595542bc292b41eb1573cdc11ef49 |
A002298 | Denominator of (2/Pi)*Integral_{0..inf} (sin x / x)^n dx. | [
"1",
"1",
"4",
"3",
"192",
"20",
"11520",
"315",
"573440",
"36288",
"928972800",
"1663200",
"54499737600",
"74131200",
"1322526965760",
"6810804000",
"228532659683328000",
"37638881280",
"16783438527143608320",
"121645100408832",
"30370031620545576960000"
] | [
"nonn",
"frac",
"easy",
"nice"
] | 32 | 0 | 5 | [
"A002297",
"A002298",
"A002304",
"A002305"
] | [
"M3217",
"N1303"
] | N. J. A. Sloane | 2018-01-11T01:09:01 | oeisdata/seq/A002/A002298.seq | 2916794faf751a9eb75c802f77213f02 |
A002299 | Binomial coefficients C(2*n+5,5). | [
"1",
"21",
"126",
"462",
"1287",
"3003",
"6188",
"11628",
"20349",
"33649",
"53130",
"80730",
"118755",
"169911",
"237336",
"324632",
"435897",
"575757",
"749398",
"962598",
"1221759",
"1533939",
"1906884",
"2349060",
"2869685",
"3478761",
"4187106",
"5006386",
"5949147",
"7028847",
"8259888",
"9657648",
"11238513"
] | [
"nonn",
"easy"
] | 61 | 0 | 5 | [
"A000389",
"A002299",
"A053127"
] | null | N. J. A. Sloane, Eric Lane | 2024-03-22T17:48:00 | oeisdata/seq/A002/A002299.seq | 2eaa29cb424afa256f567aee4e468cbe |
A002300 | Coefficients in the expansion of B^2*C^3 in Watson's notation of page 118. | [
"1",
"-2",
"-1",
"2",
"1",
"2",
"-2",
"-3",
"4",
"1",
"-5",
"-3",
"-6",
"8",
"3",
"4",
"8",
"-3",
"0",
"-2",
"-8",
"-4",
"-4",
"-13",
"9",
"5",
"18",
"-2",
"-2",
"-8",
"-3",
"10",
"0",
"-4",
"2",
"19",
"-14",
"7",
"-8",
"0",
"-20",
"-4",
"-1",
"8",
"-2",
"-15",
"-7",
"8",
"26",
"-10",
"26",
"18",
"10",
"-2",
"10",
"-28",
"-29",
"18",
"-20",
"-15",
"6",
"-8",
"8",
"-8",
"2",
"19",
"-1",
"0",
"-8",
"-6",
"28",
"-26",
"-6",
"23",
"-1",
"4",
"12",
"25",
"-36",
"-14",
"8",
"0",
"18",
"20",
"21",
"-12",
"-3",
"-9",
"0",
"-16",
"-48"
] | [
"sign",
"easy"
] | 26 | 0 | 5 | [
"A002300",
"A160553"
] | [
"M0093",
"N0029"
] | N. J. A. Sloane | 2019-01-04T04:04:45 | oeisdata/seq/A002/A002300.seq | 51abb11d95d7a2fa2e66ff434294e99c |
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