A377262 Expansion of 1/(1 - 9*x/(1 - 9*x)^(2/3))^(2/3).

1, 6, 81, 1170, 17280, 258228, 3888891, 58901256, 896105025, 13682343420, 209537016021, 3217031912808, 49497615312768, 762991150126320, 11780319846487905, 182142574910406972, 2819755778582302380, 43701602632437073050, 677982394543585361805, 10527648812452161725310

Offset: 0

Author

Seiichi Manyama, Oct 22 2024

Keywords

• nonn

Crossrefs

Cf. A377238.

Programs

PARI

a(n) = 9^n*sum(k=0, n, (-1)^k*binomial(-2/3, k)*binomial(n-k/3-1, n-k));

Formula

a(n) = 9^n * Sum_{k=0..n} (-1)^k * binomial(-2/3,k) * binomial(n-k/3-1,n-k).