OFFSET
0,3
FORMULA
a(n) ~ (2*n)! * 2^(2*n-7/4) * exp(2*sqrt(2*n)-1/2) / (n^(3/4) * Pi^(2*n+1/2)). - Vaclav Kotesovec, Jan 24 2015
MATHEMATICA
Cosh[ Tan[ x ]*x ] (* Even Part *)
nn = 20; Table[(CoefficientList[Series[Cosh[x*Tan[x]], {x, 0, 2*nn}], x] * Range[0, 2*nn]!)[[n]], {n, 1, 2*nn+1, 2}] (* Vaclav Kotesovec, Jan 24 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Extended and signs tested Mar 15 1997 by Olivier Gérard.
STATUS
approved