OFFSET
1,2
FORMULA
a(n) ~ (2*n-1)! * 4 / (sqrt(4+Pi^2) * cos(arcsinh(Pi/2)) * arcsinh(Pi/2)^(2*n)). - Vaclav Kotesovec, Jan 23 2015
MATHEMATICA
Tan[ Sinh[ x ]]/Cos[ x ] (* Odd Part *)
nn = 20; Table[(CoefficientList[Series[Sec[x]*Tan[Sinh[x]], {x, 0, 2*nn+1}], x] * Range[0, 2*nn+1]!)[[n]], {n, 2, 2*nn, 2}] (* Vaclav Kotesovec, Jan 23 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Extended and signs tested Mar 15 1997 by Olivier Gérard.
Offset changed to 1 by Vaclav Kotesovec, Jan 23 2015
STATUS
approved