cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A036081 The number of partitions of {1..(11n)} that are invariant under a permutation consisting of n 11-cycles.

Original entry on oeis.org

1, 2, 16, 202, 3044, 52794, 1055260, 24081754, 615896308, 17347970202, 531721375308, 17595339114554, 624882463734756, 23691503493287738, 954301756159098172, 40665568780962213530, 1826521141853468785364
Offset: 0

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Author

Keywords

Comments

Original name: Sorting numbers.

Crossrefs

Programs

  • Mathematica
    u[0, j_] := 1; u[k_, j_] := u[k, j] = Sum[Binomial[k-1, i-1]Plus@@(u[k-i, j]#^(i-1)&/@Divisors[j]), {i, k}]; Table[u[n, 11], {n, 0, 30}] (* Vincenzo Librandi, Dec 12 2012 - after Wouter Meeussen in similar sequences *)
    mx = 16; p = 11; Range[0, mx]! CoefficientList[ Series[ Exp[ (Exp[p*x] - p - 1)/p + Exp[x]], {x, 0, mx}], x] (* Robert G. Wilson v, Dec 12 2012 *)
    Table[Sum[Binomial[n,k] * 11^k * BellB[k, 1/11] * BellB[n-k], {k, 0, n}], {n, 0, 20}] (* Vaclav Kotesovec, Jun 29 2022 *)

Formula

E.g.f.: exp((exp(p*x)-p-1)/p+exp(x)) for p=11.
a(n) ~ exp(exp(p*r)/p + exp(r) - 1 - 1/p - n) * (n/r)^(n + 1/2) / sqrt((1 + p*r)*exp(p*r) + (1 + r)*exp(r)), where r = LambertW(p*n)/p - 1/(1 + p/LambertW(p*n) + n^(1 - 1/p) * (1 + LambertW(p*n)) * (p/LambertW(p*n))^(2 - 1/p)) for p=11. - Vaclav Kotesovec, Jul 03 2022
a(n) ~ (11*n/LambertW(11*n))^n * exp(n/LambertW(11*n) + (11*n/LambertW(11*n))^(1/11) - n - 12/11) / sqrt(1 + LambertW(11*n)). - Vaclav Kotesovec, Jul 10 2022

Extensions

New name from Danny Rorabaugh, Oct 24 2015

A141005 E.g.f. exp(sum_{d|M} (exp(d*x)-1)/d), M=8.

Original entry on oeis.org

1, 4, 31, 329, 4316, 66543, 1172077, 23139068, 504673027, 12023659317, 310112290044, 8596075462411, 254551364575929, 8012189624924740, 266901629110149847, 9374566215360038977, 346044223246303101068
Offset: 0

Views

Author

R. J. Mathar, Jul 11 2008

Keywords

Crossrefs

Column k=8 of A162663.

Programs

  • Mathematica
    u[0, j_]: = 1; u[k_, j_]: = u[k, j] = Sum[Binomial[k-1, i-1]Plus@@(u[k-i, j]#^(i-1)&/@Divisors[j]), {i, k}]; Table[u[n, 8], {n, 0, 30}] (* Vincenzo Librandi, Dec 12 2012 *)

A141006 E.g.f. exp(sum_{d|M} (exp(d*x)-1)/d), M=9.

Original entry on oeis.org

1, 3, 22, 235, 3139, 49376, 891491, 18160071, 411124024, 10212362573, 275543711899, 8012352809874, 249516568317597, 8277748828228015, 291219448755079278, 10821916875914147551, 423314732431005599479
Offset: 0

Views

Author

R. J. Mathar, Jul 11 2008

Keywords

Crossrefs

Column k=9 of A162663.

Programs

  • Mathematica
    u[0, j_]: = 1; u[k_, j_]: = u[k, j] = Sum[Binomial[k-1, i-1]Plus@@(u[k-i, j]#^(i-1)&/@Divisors[j]), {i, k}]; Table[u[n, 9], {n, 0, 30}](* Vincenzo Librandi, Dec 12 2012 *)

A141007 E.g.f. exp(sum_{d|M} (exp(d*x)-1)/d), M=10.

Original entry on oeis.org

1, 4, 34, 410, 6170, 109506, 2227882, 50987378, 1293386410, 35933906946, 1083069266634, 35146231883122, 1220316225699786, 45099576850647106, 1766204747811044266, 73012853049788936050, 3175271515525778312810
Offset: 0

Views

Author

R. J. Mathar, Jul 11 2008

Keywords

Crossrefs

Column k=10 of A162663.

Programs

  • Mathematica
    u[0, j_]: = 1; u[k_, j_]: = u[k, j] = Sum[Binomial[k-1, i-1]Plus@@(u[k-i, j]#^(i-1)&/@Divisors[j]), {i, k}]; Table[u[n, 10], {n, 0, 30}] (* Vincenzo Librandi, Dec 12 2012 *)

A141008 E.g.f. exp(sum_{d|M} (exp(d*x)-1)/d), M=12.

Original entry on oeis.org

1, 6, 64, 930, 16780, 356922, 8681380, 236739354, 7135453180, 235079261562, 8389974421012, 322019941283514, 13211434169884204, 576435716324437722, 26631611751773999044, 1297943388416061780186
Offset: 0

Views

Author

R. J. Mathar, Jul 11 2008

Keywords

Crossrefs

Column k=12 of A162663.

Programs

  • Mathematica
    u[0, j_]: = 1; u[k_, j_]: = u[k, j] = Sum[Binomial[k-1, i-1]Plus@@(u[k-i, j]#^(i-1)&/@Divisors[j]), {i, k}]; Table[u[n, 12], {n, 0, 30}] (* Vincenzo Librandi, Dec 12 2012 *)

A141009 E.g.f. exp(Sum_{d|M} (exp(d*x)-1)/d), M=13.

Original entry on oeis.org

1, 2, 18, 262, 4498, 88174, 1989162, 51366438, 1491069602, 47749828830, 1664928894170, 62693869629142, 2534737217687378, 109469680507411214, 5025930552213949450, 244236790780300327302, 12515419830686362586882
Offset: 0

Views

Author

R. J. Mathar, Jul 11 2008

Keywords

Comments

Also the number of partitions of {1..(13n)} that are invariant under a permutation consisting of n 13-cycles. - Danny Rorabaugh, Oct 29 2015

Crossrefs

Column 13 of A162663.

Programs

  • Mathematica
    u[0, j_]: = 1; u[k_, j_]: = u[k, j] = Sum[Binomial[k-1, i-1]Plus@@(u[k-i, j]#^(i-1)&/@Divisors[j]), {i, k}]; Table[u[n, 13], {n, 0, 30}] (* Vincenzo Librandi, Dec 12 2012, after Wouter Meeussen in similar sequences *)
    mx = 16; p = 13; Range[0, mx]! CoefficientList[ Series[ Exp[ (Exp[p*x] - p - 1)/p + Exp[x]], {x, 0, mx}], x] (* Robert G. Wilson v, Dec 12 2012 *)

A141010 E.g.f. exp(sum_{d|M} (exp(d*x)-1)/d), M=14.

Original entry on oeis.org

1, 4, 40, 602, 11384, 253698, 6495616, 187940402, 6055160152, 214444348674, 8261055193008, 343357357970866, 15298169514407880, 726752780487465922, 36642712015230282784, 1952976182776961017138
Offset: 0

Views

Author

R. J. Mathar, Jul 11 2008

Keywords

Crossrefs

Column k=14 of A162663.

Programs

  • Mathematica
    u[0, j_]: = 1; u[k_, j_]: = u[k, j] = Sum[Binomial[k-1, i-1]Plus@@(u[k-i, j]#^(i - 1)&/@Divisors[j]), {i, k}]; Table[u[n, 14], {n, 0, 30}] (* Vincenzo Librandi, Dec 12 2012 *)

A141011 E.g.f. exp(sum_{d|M} (exp(d*x)-1)/d), M=15.

Original entry on oeis.org

1, 4, 40, 612, 11976, 276836, 7336248, 219610532, 7331824360, 269576919908, 10796426089880, 466904884431268, 21658080409800264, 1071807203930733668, 56328256034260866296, 3131089417758323092388
Offset: 0

Views

Author

R. J. Mathar, Jul 11 2008

Keywords

Crossrefs

Column k=15 of A162663.

Programs

  • Mathematica
    u[0, j_]: = 1; u[k_, j_]: = u[k, j] = Sum[Binomial[k-1, i-1]Plus@@(u[k-i, j]#^(i-1)&/@Divisors[j]), {i, k}]; Table[u[n, 15], {n, 0, 30}] (* Vincenzo Librandi, Dec 12 2012 *)

A162664 a(n) = sigma(n) + tau(n)^2.

Original entry on oeis.org

2, 7, 8, 16, 10, 28, 12, 31, 22, 34, 16, 64, 18, 40, 40, 56, 22, 75, 24, 78, 48, 52, 28, 124, 40, 58, 56, 92, 34, 136, 36, 99, 64, 70, 64, 172, 42, 76, 72, 154, 46, 160, 48, 120, 114, 88, 52, 224, 66, 129, 88, 134, 58, 184, 88, 184, 96, 106, 64, 312, 66, 112, 140, 176, 100
Offset: 1

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Author

Keywords

Comments

Row 2 of A162663.

Crossrefs

Programs

  • Mathematica
    Table[DivisorSigma[1, n] + DivisorSigma[0, n]^2, {n, 65}] (* Robert A. Russell, Apr 28 2018 *)
  • PARI
    a(n) = sigma(n) + numdiv(n)^2; \\ Michel Marcus, Apr 28 2018

A162665 a(n) = sigma_2(n) + 3 sigma(n) tau(n) + tau(n)^3.

Original entry on oeis.org

5, 31, 42, 111, 70, 258, 106, 329, 235, 410, 202, 930, 262, 602, 612, 931, 406, 1373, 490, 1518, 948, 1106, 682, 2802, 957, 1418, 1364, 2274, 1030, 3540, 1162, 2715, 1860, 2162, 1940, 5097, 1606, 2594, 2436, 4882, 1942, 5316, 2122, 4290, 3986, 3578, 2506
Offset: 1

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Author

Keywords

Comments

Row 3 of A162663.

Crossrefs

Programs

  • Mathematica
    Table[DivisorSigma[2,n]+3DivisorSigma[1,n]DivisorSigma[0,n]+ DivisorSigma[ 0,n]^3,{n,50}] (* Harvey P. Dale, Jun 22 2013 *)
  • PARI
    a(n) = my(f = factor(n), d = numdiv(f)); sigma(f, 2) + 3 * d * sigma(f) + d^3; \\ Amiram Eldar, Jan 02 2025
Previous Showing 11-20 of 21 results. Next