A372013 G.f. A(x) satisfies A(x) = 1/( 1 + x*(1 - 9*x*A(x))^(1/3) ).

1, -1, 4, -1, 46, 149, 1351, 8441, 63499, 462752, 3514807, 26923478, 209566927, 1647633779, 13079663527, 104649229988, 843120766711, 6833665175513, 55683581174641, 455878084448132, 3748025535972448, 30931714278955736, 256150668109462507

Offset

0,3

Links

Table of n, a(n) for n=0..22.

Formula

a(n) = (-1)^n * Sum_{k=0..n} 9^(n-k) * binomial(n,k) * binomial(k/3,n-k)/(n-k+1).

Prog

(PARI) a(n) = (-1)^n*sum(k=0, n, 9^(n-k)*binomial(n, k)*binomial(k/3, n-k)/(n-k+1));

Crossrefs

Cf. A166587, A362155, A372012.

Sequence in context: A060627 A113101 A365088 * A316159 A370415 A113112

Adjacent sequences: A372010 A372011 A372012 * A372014 A372015 A372016

Keyword

sign

Author

Seiichi Manyama, Apr 19 2024

Status

approved