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.

A023005 Number of partitions of n into parts of 6 kinds.

Original entry on oeis.org

1, 6, 27, 98, 315, 918, 2492, 6372, 15525, 36280, 81816, 178794, 380051, 788004, 1597725, 3174210, 6190182, 11867310, 22395359, 41650050, 76413078, 138421358, 247783113, 438616728, 768291650, 1332444330, 2289213495, 3898064226, 6581591157, 11023247880
Offset: 0

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Comments

a(n) is Euler transform of A010722. - Alois P. Heinz, Oct 17 2008

Crossrefs

Cf. 6th column of A144064. - Alois P. Heinz, Oct 17 2008

Programs

  • Maple
    with(numtheory): a:=proc(n) option remember; `if`(n=0, 1, add(add(d*6, d=divisors(j)) *a(n-j), j=1..n)/n) end: seq(a(n), n=0..40); # Alois P. Heinz, Oct 17 2008
  • Mathematica
    nmax=50; CoefficientList[Series[Product[1/(1-x^k)^6,{k,1,nmax}],{x,0,nmax}],x] (* Vaclav Kotesovec, Feb 28 2015 *)

Formula

G.f.: Product_{m>=1} 1/(1-x^m)^6.
a(n) ~ exp(2 * Pi * sqrt(n)) / (16 * n^(9/4)). - Vaclav Kotesovec, Feb 28 2015
a(0) = 1, a(n) = (6/n)*Sum_{k=1..n} A000203(k)*a(n-k) for n > 0. - Seiichi Manyama, Mar 26 2017
G.f.: exp(6*Sum_{k>=1} x^k/(k*(1 - x^k))). - Ilya Gutkovskiy, Feb 06 2018