A022641 Expansion of Product_{m>=1} (1 + m*q^m)^13.

1, 13, 104, 663, 3614, 17576, 78299, 324766, 1269242, 4715204, 16762551, 57327556, 189418658, 606787572, 1890046210, 5738539729, 17019191579, 49394158541, 140507716414, 392299039821, 1076369417474, 2905414115877, 7722941644821, 20233362612424, 52288914446548, 133389316899462

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 0..1000

Crossrefs

Column k=13 of A297321.

Programs

Magma

Coefficients(&*[(1+m*x^m)^13:m in [1..40]])[1..40] where x is PolynomialRing(Integers()).1; // G. C. Greubel, Feb 17 2018

Maple

[seq(coeff(series(mul((1+m*q^m)^(13), m=1..100),q,101),q,j),j=0..25)]; # Muniru A Asiru, Feb 18 2018

Mathematica

With[{nmax = 50}, CoefficientList[Series[Product[(1 + k*q^k)^13, {k, 1, nmax}], {q, 0, nmax}], q]] (* G. C. Greubel, Feb 17 2018 *)

PARI

m=50; q='q+O('q^m); Vec(prod(n=1,m,(1+n*q^n)^13)) \\ G. C. Greubel, Feb 17 2018