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.

A292194 Sum of n-th powers of products of terms in all partitions of n.

Original entry on oeis.org

1, 1, 5, 36, 610, 13225, 1173652, 92137513, 27960729094, 14612913824364, 11885159817456154, 23676862215173960082, 144210774157588042096815, 778807208565930895328294712, 15863318347221014170216633451982, 908978343753718115412387406378667615
Offset: 0

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Author

Seiichi Manyama, Sep 11 2017

Keywords

Examples

			5 = 4 + 1 = 3 + 2 = 3 + 1 + 1 = 2 + 2 + 1 = 2 + 1 + 1 + 1 = 1 + 1 + 1 + 1 + 1.
So a(5) = 5^5 + (4*1)^5 + (3*2)^5 + (3*1*1)^5 + (2*2*1)^5 + (2*1*1*1)^5 + (1*1*1*1*1)^5 = 13225.
		

Crossrefs

Main diagonal of A292193.
Cf. A292190.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0 or i=1, 1,
          `if`(i>n, 0, i^k*b(n-i, i, k))+b(n, i-1, k))
        end:
    a:= n-> b(n$3):
    seq(a(n), n=0..20);  # Alois P. Heinz, Sep 11 2017
  • Mathematica
    nmax = 20; Table[SeriesCoefficient[Product[1/(1 - k^n*x^k), {k, 1, n}], {x, 0, n}], {n, 0, nmax}] (* Vaclav Kotesovec, Sep 15 2017 *)
  • PARI
    {a(n) = polcoeff(1/prod(k=1, n, 1-k^n*x^k+x*O(x^n)), n)}

Formula

a(n) = [x^n] Product_{k=1..n} 1/(1 - k^n*x^k).
From Vaclav Kotesovec, Sep 15 2017: (Start)
a(n) ~ 3^(n^2/3) if mod(n,3)=0
a(n) ~ 3^(n*(n-4)/3)*2^(2*n+1) if mod(n,3)=1
a(n) ~ 3^(n*(n-2)/3)*2^n if mod(n,3)=2
(End)