A117415 E.g.f. (x*tan(x)-x^2)/8 (even powers only).

0, 0, 1, 12, 272, 9920, 530688, 39144448, 3807514624, 472197021696, 72722212782080, 13616619646091264, 3046271659520557056, 802494810618175946752, 245880605613803859607552, 86696940704285991905525760, 34855851028500677184683245568

Offset: 0

Author

Paul Barry, Mar 13 2006

Keywords

• easy
• nonn

Crossrefs

Column k=2 of Euler triangle A117414.

Programs

Mathematica

With[{nn=40},Take[CoefficientList[Series[(x*Tan[x]-x^2)/8,{x,0,nn}],x] Range[0,nn]!,{1,-1,2}]] (* Harvey P. Dale, May 06 2014 *)

Formula

a(n) = 2^(2*n-1) * (2^(2*n)-1) * abs(Bernoulli(2*n))/4 - (C(1,n) - C(0,n))/4.

Extensions

More terms from Harvey P. Dale, May 06 2014