OFFSET
0,3
FORMULA
a(n) ~ (n-1)! / (2 * r^n), where r = 0.606555409757505028513842694060977136299... is the root of the equation arctan(r)*exp(r) = 1. - Vaclav Kotesovec, Feb 05 2015
MATHEMATICA
With[{nn=25}, CoefficientList[Series[ArcTanh[ArcTan[x]Exp[x]], {x, 0, nn}], x]Range[0, nn]!] (* Harvey P. Dale, Oct 21 2011 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
EXTENSIONS
Prepended missing a(0)=0 from Vaclav Kotesovec, Feb 05 2015
STATUS
approved