A056197 Diagonal of A056151.

1, 7, 38, 222, 1464, 10920, 91440, 851760, 8749440, 98340480, 1201132800, 15846969600, 224651750400, 3406180377600, 55009501747200, 942833219328000, 17093919338496000, 326876746420224000, 6575237795782656000

Offset: 0

Author

N. J. A. Sloane, Aug 05 2000

Keywords

• nonn
• easy

Crossrefs

Cf. A056151.

Programs

Mathematica

Table[(3n(n+1)+1)n!, {n, 0, 18}]

Formula

a(n)=(3n^2+3n+1)n!=((n+1)^3-n^3)n!=n!A003215(n). - Paul Barry, Apr 02 2003

E.g.f.: (1 + 4*x + x^2)/(1 - x)^3. - Ilya Gutkovskiy, May 12 2017

Extensions

More terms from Wouter Meeussen, Aug 05 2000