A183205 a(n) = [x^n] (1-x)^(3n+1)/(n+1) * Sum_{k>=0} C(n+k-1,k)^3*x^k.

1, 2, 16, 190, 2768, 45584, 814728, 15439974, 305760400, 6265985440, 131980086368, 2843029539376, 62400628835608, 1391503990134080, 31454839290752912, 719470742267557110, 16627360903974831120, 387786053931422003360

Offset: 0

Author

Paul D. Hanna, Dec 30 2010

Keywords

• nonn

Crossrefs

Cf. A181544, A183204.

Programs

PARI

{a(n)=polcoeff((1-x)^(3*n+1)/(n+1)*sum(j=0, 2*n, binomial(n+j, j)^3*x^j), n)}

Formula

a(n) = A183204(n)/(n+1), where A183204 equals the central terms of triangle A181544.