A379026 a(n) = Sum_{k=0..n} binomial(4*n+k-1,k) * binomial(4*n+k,n-k).

1, 8, 136, 2612, 52888, 1103248, 23458756, 505519792, 11001461560, 241240165796, 5321735043496, 117969960106380, 2625673485660100, 58638653062716488, 1313363972969179904, 29489827322243843032, 663600214363813934328, 14961465721142755457484

Offset

0,2

Links

Table of n, a(n) for n=0..17.

Formula

a(n) = [x^n] ( (1 + x)/(1 - x - x^2) )^(4*n).

Prog

(PARI) a(n) = sum(k=0, n, binomial(4*n+k-1, k)*binomial(4*n+k, n-k));

Crossrefs

Cf. A262910, A379022, A379025.

Cf. A379024.

Sequence in context: A072072 A386561 A195614 * A358958 A131927 A132869

Adjacent sequences: A379023 A379024 A379025 * A379027 A379028 A379029

Keyword

nonn

Author

Seiichi Manyama, Dec 14 2024

Status

approved