OFFSET
0,3
FORMULA
a(n) = [x^n] 1/(1 - n^3*x - x^2).
a(n) ~ n^(3*n). - Vaclav Kotesovec, Jan 09 2024
MATHEMATICA
Join[{1}, Table[n^(3*n) * Hypergeometric2F1[1/2 - n/2, -n/2, -n, -4/n^6], {n, 1, 15}]] (* Vaclav Kotesovec, Jan 09 2024 *)
PROG
(PARI) a(n) = sum(k=0, n\2, n^(3*(n-2*k))*binomial(n-k, k));
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Jan 09 2024
STATUS
approved