OFFSET
0,3
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..300
FORMULA
a(n) = [x^(10*n)] (Sum_{k=0..20} x^k)^n.
a(n) ~ sqrt(3) * 21^n / (2*sqrt(55*Pi*n)). - Vaclav Kotesovec, Dec 15 2018
MAPLE
seq(add((-1)^k*binomial(n, k)*binomial(11*n-21*k-1, n-1), k = 0..floor(n/2)), n = 0..20); # Peter Bala, Oct 19 2024
MATHEMATICA
a[n_] := If[n==0, 1, Coefficient[Expand[Sum[x^k, {k, 0, 20}]^n], x^(10n)]]; Array[a, 25, 0] (* Amiram Eldar, Dec 14 2018 *)
PROG
(PARI) {a(n) = polcoeff((sum(k=0, 20, x^k))^n, 10*n, x)}
CROSSREFS
KEYWORD
nonn,changed
AUTHOR
Seiichi Manyama, Dec 14 2018
STATUS
approved