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

0,2

Links

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

Formula

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

Prog

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

Crossrefs

Cf. A181544, A183204.

Sequence in context: A291816 A123898 A118644 * A006335 A273591 A292347

Adjacent sequences: A183202 A183203 A183204 * A183206 A183207 A183208

Keyword

nonn

Author

Paul D. Hanna, Dec 30 2010

Status

approved