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.

A023021 Number of partitions of n into parts of 23 kinds.

Original entry on oeis.org

1, 23, 299, 2852, 22126, 147407, 871838, 4680845, 23177583, 107100903, 466066181, 1923780950, 7576060505, 28601630657, 103928814438, 364712523658, 1239637963457, 4091266414235, 13139808783725, 41145568478988, 125833948024603, 376417734772625, 1102878148698235
Offset: 0

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Comments

a(n) is Euler transform of A010862. - Alois P. Heinz, Oct 17 2008
Convolved with A000041 = A006922. - Gary W. Adamson, Jun 09 2009

Crossrefs

Cf. 23rd column of A144064. - Alois P. Heinz, Oct 17 2008
Cf. A006922, A000041. - Gary W. Adamson, Jun 09 2009

Programs

  • Maple
    with (numtheory): a:= proc(n) option remember; `if`(n=0, 1, add (add (d*23, d=divisors(j)) *a(n-j), j=1..n)/n) end: seq (a(n), n=0..40); # Alois P. Heinz, Oct 17 2008
  • Mathematica
    CoefficientList[1/QPochhammer[q]^23 + O[q]^30, q] (* Jean-François Alcover, Dec 03 2015 *)
  • PARI
    Vec(1/eta(x)^23 + O(x^30)) \\ Indranil Ghosh, Mar 27 2017

Formula

G.f.: Product_{m>=1} 1/(1-x^m)^23.
a(0) = 1, a(n) = (23/n)*Sum_{k=1..n} A000203(k)*a(n-k) for n > 0. - Seiichi Manyama, Mar 27 2017
a(n) ~ m^((m+1)/4) * exp(Pi*sqrt(2*m*n/3)) / (2^((3*m+5)/4) * 3^((m+1)/4) * n^((m+3)/4)) * (1 - ((9+Pi^2)*m^2+36*m+27) / (24*Pi*sqrt(6*m*n))), set m = 23. - Vaclav Kotesovec, Jun 28 2025