A009392 Expansion of e.g.f.: log(1+tanh(x))/cosh(x).

0, 1, -1, -3, 8, 25, -121, -427, 3128, 12465, -124921, -555731, 7158128, 35135945, -557749921, -2990414715, 56767019408, 329655706465, -7316056402321, -45692713833379, 1164842760597368, 7777794952988025, -224574978081433321

Offset: 0

Author

R. H. Hardin

Keywords

• sign
• easy

Programs

Mathematica

With[{nn=30},CoefficientList[Series[Log[1+Tanh[x]]/Cosh[x],{x,0,nn}],x] Range[ 0,nn]!] (* Harvey P. Dale, Oct 06 2014 *)

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Definition clarified and prior Mathematica program replaced by Harvey P. Dale, Oct 06 2014