OFFSET
0,2
FORMULA
a(n) ~ (-1)^n * 2^(2*n+2) * n^(2*n) * cos(tanh(Pi/2)) / ((cosh(Pi)+1) * exp(2*n)). - Vaclav Kotesovec, Oct 30 2013
MATHEMATICA
Table[n!*SeriesCoefficient[Sinh[Tan[ArcSinh[x]]], {x, 0, n}], {n, 1, 40, 2}] (* Vaclav Kotesovec, Oct 30 2013 *)
CROSSREFS
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
STATUS
approved