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

0,4

Links

Table of n, a(n) for n=0..16.

Formula

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

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 *)

Crossrefs

Column k=2 of Euler triangle A117414.

Sequence in context: A107485 A293270 A341815 * A152129 A115461 A169961

Adjacent sequences: A117412 A117413 A117414 * A117416 A117417 A117418

Keyword

easy,nonn

Author

Paul Barry, Mar 13 2006

Extensions

More terms from Harvey P. Dale, May 06 2014

Status

approved