OFFSET
0,2
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 0..212
FORMULA
a(n) ~ c * (-1)^n * (2*n)! / (sqrt(n) * (arctan(arcsinh(1)))^(2*n)), where c = 1.0522205751764250070089302438417471228756... . - Vaclav Kotesovec, Feb 04 2015
MATHEMATICA
nn = 20; Table[(CoefficientList[Series[ArcSinh[Sin[Tanh[x]]], {x, 0, 2*nn+1}], x] * Range[0, 2*nn+1]!)[[n]], {n, 2, 2*nn, 2}] (* Vaclav Kotesovec, Feb 04 2015 *)
CROSSREFS
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
STATUS
approved