A366699 G.f. satisfies A(x) = (1 + x)^3 + x*A(x)^4.

1, 4, 19, 173, 1860, 21814, 271388, 3515330, 46906860, 640321565, 8899950644, 125524292790, 1791943900656, 25843064347685, 375956017001280, 5510454405453368, 81297696816798684, 1206334991431968912, 17991734573723974384, 269560224872407933010

Offset

0,2

Links

Table of n, a(n) for n=0..19.

Formula

a(n) = Sum_{k=0..n} binomial(3*(3*k+1),n-k) * binomial(4*k,k)/(3*k+1).

Prog

(PARI) a(n) = sum(k=0, n, binomial(3*(3*k+1), n-k)*binomial(4*k, k)/(3*k+1));

Crossrefs

Cf. A366267, A366698, A366700.

Cf. A364624.

Sequence in context: A249785 A341379 A155804 * A292167 A126147 A007411

Adjacent sequences: A366696 A366697 A366698 * A366700 A366701 A366702

Keyword

nonn

Author

Seiichi Manyama, Oct 16 2023

Status

approved