OFFSET
1,2
LINKS
Robert Israel, Table of n, a(n) for n = 1..225
FORMULA
a(n) ~ (2*n-1)! * 8 * cosh(arctan(Pi/2)) / ((4+Pi^2) * arctan(Pi/2)^(2*n)). - Vaclav Kotesovec, Jan 23 2015
MAPLE
S:= series(tan(tan(x))*cosh(x), x, 40):
seq(coeff(S, x, j)*j!, j=1..39, 2); # Robert Israel, Feb 19 2018
MATHEMATICA
Tan[ Tan[ x ]]*Cosh[ x ] (* Odd Part *)
nn = 20; Table[(CoefficientList[Series[Cosh[x]*Tan[Tan[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 by Olivier Gérard, Mar 15 1997
Offset changed to 1 by Vaclav Kotesovec, Jan 23 2015
STATUS
approved