OFFSET
0,2
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..1000
FORMULA
a(n) ~ 3^(1/4) * exp(Pi * sqrt(3*n)) / (64 * n^(3/4)). - Vaclav Kotesovec, Mar 05 2015
a(0) = 1, a(n) = (9/n)*Sum_{k=1..n} A000593(k)*a(n-k) for n > 0. - Seiichi Manyama, Apr 03 2017
G.f.: exp(9*Sum_{k>=1} (-1)^(k+1)*x^k/(k*(1 - x^k))). - Ilya Gutkovskiy, Feb 06 2018
MATHEMATICA
nmax=50; CoefficientList[Series[Product[(1+q^m)^9, {m, 1, nmax}], {q, 0, nmax}], q] (* Vaclav Kotesovec, Mar 05 2015 *)
PROG
(PARI) m=50; q='q+O('q^m); Vec(prod(n=1, m, (1+q^n)^9)) \\ G. C. Greubel, Feb 26 2018
(Magma) Coefficients(&*[(1+x^m)^9:m in [1..40]])[1..40] where x is PolynomialRing(Integers()).1; // G. C. Greubel, Feb 26 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved