A364478 G.f. satisfies A(x) = 1 + x*A(x)^3 + x^2*A(x)^8.

1, 1, 4, 23, 154, 1124, 8675, 69626, 575243, 4859778, 41789764, 364565277, 3218581695, 28702642553, 258172627259, 2339496034381, 21337716782873, 195726876816623, 1804472496834650, 16711389876481027, 155395461519245354, 1450298253483719944

Offset

0,3

Links

Table of n, a(n) for n=0..21.

Formula

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

Prog

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

Crossrefs

Cf. A002293, A104979, A186997, A255673, A361245, A364474, A364475.

Sequence in context: A246813 A369213 A055723 * A271469 A366070 A374564

Adjacent sequences: A364475 A364476 A364477 * A364479 A364480 A364481

Keyword

nonn

Author

Seiichi Manyama, Jul 26 2023

Status

approved