OFFSET
0,2
FORMULA
a(n) ~ (2*n)! * 8 * Pi / ((4+Pi^2)^(3/2) * arctan(Pi/2)^(2*n+1)). - Vaclav Kotesovec, Jan 23 2015
MATHEMATICA
Tan[ Tan[ x ] ]*Sin[ x ] (* Even Part *)
nn = 20; Table[(CoefficientList[Series[Sin[x]*Tan[Tan[x]], {x, 0, 2*nn}], x] * Range[0, 2*nn]!)[[n]], {n, 1, 2*nn+1, 2}] (* Vaclav Kotesovec, Jan 23 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Extended and signs tested Mar 15 1997 by Olivier Gérard.
STATUS
approved