A054131 T(2n,n), array T as in A054126.

2, 5, 24, 134, 802, 4960, 31212, 198504, 1271754, 8192780, 53009614, 344213930, 2241814696, 14637778784, 95786210880

Offset

0,1

Links

Table of n, a(n) for n=0..14.

Formula

a(n) = A052509(4*n,3*n+1) + A052509(4*n,n) = 2^(n-1) + Sum_{m=0..n} binomial(3*n,m). for n >= 1. - Jianing Song, May 30 2022

Prog

(PARI) a(n) = if(n==0, 2, 2^(n-1) + sum(m=0, n, binomial(3*n, m))) \\ Jianing Song, May 30 2022

Crossrefs

Cf. A054126.

Sequence in context: A208969 A020022 A026073 * A086635 A020124 A012249

Adjacent sequences: A054128 A054129 A054130 * A054132 A054133 A054134

Keyword

nonn

Author

Clark Kimberling

Status

approved