A024231 - OEIS

%I #10 Aug 26 2020 18:12:51

%S 0,1,-2,-21,-228,5077,631834,37060863,791278008,-198249695063,

%T -43572627802442,-5264284574193645,-189769141997109804,

%U 100566175129622055037,26413749605638836403666

%N Expansion of tanh(tan(x))*sin(x)/2.

%t With[{nn=30},Take[CoefficientList[Series[Tanh[Tan[x]]*Sin[x]/2,{x,0,nn}],x] Range[0,nn]!,{1,-1,2}]] (* _Harvey P. Dale_, Aug 26 2020 *)

%Y Cf. A009811.

%K sign

%O 0,3

%A _R. H. Hardin_

%E Extended with signs Mar 1997

%E Previous Mathematica program replaced by _Harvey P. Dale_, Aug 26 2020