OFFSET
0,4
FORMULA
a(n) ~ 2*n^(n-1) * exp(-n) * (2*Pi*cos(n*Pi/2) + 4*cos(1)*sin(n*Pi/2)) / (2+Pi^2+2*cos(2)). - Vaclav Kotesovec, Nov 01 2013
MATHEMATICA
CoefficientList[Series[Log[Cosh[x]+ArcSinh[x]], {x, 0, 20}], x]* Range[0, 20]! (* Vaclav Kotesovec, Nov 01 2013 *)
CROSSREFS
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
EXTENSIONS
Prepended missing a(0)=0 from Vaclav Kotesovec, Nov 01 2013
STATUS
approved