A379192 G.f. A(x) satisfies A(x) = (1 + x*A(x))^3/(1 - x*A(x)^2).

1, 4, 27, 235, 2344, 25374, 289906, 3441015, 42017262, 524418639, 6660297019, 85796763321, 1118314903447, 14722203914653, 195465862293738, 2614323606027841, 35191188308646852, 476390139438508209, 6481416282265645008, 88577523301166187997, 1215421503348039618483

Offset

0,2

Links

Table of n, a(n) for n=0..20.

Formula

a(n) = Sum_{k=0..n} binomial(n+2*k+1,k) * binomial(3*n+3*k+3,n-k)/(n+2*k+1).

Prog

(PARI) a(n) = sum(k=0, n, binomial(n+2*k+1, k)*binomial(3*n+3*k+3, n-k)/(n+2*k+1));

Crossrefs

Cf. A307678, A379191.

Sequence in context: A160883 A362274 A328978 * A185655 A181146 A303559

Adjacent sequences: A379189 A379190 A379191 * A379193 A379194 A379195

Keyword

nonn

Author

Seiichi Manyama, Dec 17 2024

Status

approved