OFFSET
0,4
FORMULA
a(n) ~ (n-1)! * (2*n)^(cosh(1)/2) / GAMMA(cosh(1)/2). - Vaclav Kotesovec, Oct 24 2013
MATHEMATICA
CoefficientList[Series[Exp[Cosh[x]*ArcTanh[x]], {x, 0, 20}], x]* Range[0, 20]! (* Vaclav Kotesovec, Oct 24 2013 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
STATUS
approved