A009665 E.g.f. tan(sin(x))*sin(x) (even powers only).

0, 2, 0, -32, -640, 1024, 661504, 25305088, -948699136, -216606572544, -10006005547008, 2013855760777216, 462400685741178880, 10633324821284388864, -16549579084211148554240

Offset

0,2

Links

Table of n, a(n) for n=0..14.

Formula

a(n)=sum(k=1..n, ((sum(j=1..2*k-1, j!*(-1)^(j)*2^(2*n-j)*stirling2(2*k-1,j)))*sum(i=0..k, (i-k)^(2*n)*binomial(2*k,i)*(-1)^(n-i)))/((2*k-1)!)). - Vladimir Kruchinin, Jun 29 2011

Prog

(Maxima)
a(n):=sum(((sum(j!*(-1)^(j)*2^(2*n-j)*stirling2(2*k-1, j), j, 1, 2*k-1))*sum((i-k)^(2*n)*binomial(2*k, i)*(-1)^(n-i), i, 0, k))/((2*k-1)!), k, 1, n); /* Vladimir Kruchinin, Jun 29 2011 */

Crossrefs

Sequence in context: A156473 A156504 A340545 * A053552 A009548 A172388

Adjacent sequences: A009662 A009663 A009664 * A009666 A009667 A009668

Keyword

sign

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Status

approved