A009261 - OEIS

%I #15 Apr 01 2017 13:22:16

%S 1,1,1,-3,-15,33,513,-403,-31007,-41247,2881089,12404989,-376412847,

%T -3175861439,64825974593,925805229229,-13951231536191,

%U -320290449542079,3556538162237313,131747901365358205,-998391201911168335

%N E.g.f.: Expansion of exp(tanh(tanh(x))).

%t With[{nn=30},CoefficientList[Series[Exp[Tanh[Tanh[x]]],{x,0,nn}],x] Range[0,nn]!] (* _Harvey P. Dale_, Apr 08 2013 *)

%K sign,easy

%O 0,4

%A _R. H. Hardin_

%E Extended with signs by _Olivier Gérard_, Mar 15 1997

%E Definition clarified by _Harvey P. Dale_, Apr 08 2013