OFFSET
0,3
REFERENCES
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..100
FORMULA
a(n) = Sum_{m=1..n} ( Sum_{k=0..2*n-2*m} binomial(2*m+k-1,2*m-1) * (2*m+k)! * (-1)^k * 2^(2*n-2*m-k) * Stirling2(2*n,2*m+k) )/(2*m)!, n>0, a(0)=1. - Vladimir Kruchinin, Jun 10 2011
MATHEMATICA
nn = 20; Table[(CoefficientList[Series[Cos[Tanh[x]], {x, 0, 2*nn}], x] * Range[0, 2*nn]!)[[n]], {n, 1, 2*nn+1, 2}] (* Vaclav Kotesovec, Feb 16 2015 *)
PROG
(Maxima)
a(n):=sum((sum(binomial(2*m+k-1, 2*m-1)*(2*m+k)!*(-1)^(k)*2^(2*n-2*m-k)*stirling2(2*n, 2*m+k), k, 0, 2*n-2*m))/(2*m)!, m, 1, n); /* Vladimir Kruchinin, Jun 10 2011 */
CROSSREFS
KEYWORD
sign
AUTHOR
STATUS
approved