OFFSET
0,3
FORMULA
a(n) ~ n! / ((Pi/2 + exp(r)/sqrt(1+r^2)) * r^(n+1)), where r = 0.782048434734397136830260131892318660005898990290325... is the root of the equation arcsinh(r)*exp(r) = Pi/2. - Vaclav Kotesovec, Feb 06 2015
MATHEMATICA
With[{nn=20}, Join[{0}, Rest[CoefficientList[Series[Tan[ArcSinh[x]Exp[x]], {x, 0, nn}], x]Range[0, nn]!]]] (* Harvey P. Dale, May 07 2012 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
STATUS
approved