A010793 a(n) = n!*(n+4)! / 4!.

1, 5, 60, 1260, 40320, 1814400, 108864000, 8382528000, 804722688000, 94152554496000, 13181357629440000, 2174924008857600000, 417585409700659200000, 92286375543845683200000, 23256166637049112166400000, 6628007491558996967424000000

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn

Links

• Delbert L. Johnson, Table of n, a(n) for n = 0..251
• Index entries for sequences related to factorial numbers.

Crossrefs

Cf. A010791, A010792, A010794, A010795.

Programs

Maple

f := n->n!*(n+4)!/4!;

Mathematica

Table[n! * (n + 4)!/24, {n, 0, 20}] (* Amiram Eldar, Sep 27 2022 *)

PARI

a(n) = n!*(n+4)! / 4!; \\ Michel Marcus, Mar 30 2023

Formula

From Amiram Eldar, Sep 27 2022: (Start)

Sum_{n>=0} 1/a(n) = 24*BesselI(4,2).

Sum_{n>=0} (-1)^n/a(n) = 24*BesselJ(4,2). (End)

a(n) = 1/([x^n] hypergeom([], [5], x)). - Peter Luschny, Sep 13 2024