A321957 a(n) = binomial(3*n, n + 1)*hypergeom([1, 1 - 2*n], [2 + n], -1).

0, 4, 42, 382, 3302, 27824, 230964, 1898712, 15505590, 126025204, 1020732722, 8245721686, 66477664088, 535118039200, 4302260308416, 34556369687312, 277350672112822, 2224673611151996, 17835746776558638, 142937183041928874, 1145145456194522262, 9171991364052010176

Offset: 0

Author

Peter Luschny, Nov 22 2018

Keywords

• nonn

Programs

Maple

A321957 := n -> binomial(3*n, n+1)*hypergeom([1, 1 - 2*n], [2 + n], -1):
[seq(A321957(n), n=0..21)]: simplify(%);

Mathematica

Table[Binomial[3*n, n+1] * HypergeometricPFQ[{1, 1 - 2*n}, {2 + n}, -1], {n, 0, 20}] (* Vaclav Kotesovec, Feb 17 2024 *)

Formula

a(n) ~ 8^n. - Vaclav Kotesovec, Feb 17 2024