A024249 - OEIS

%I #8 Jan 30 2023 12:01:04

%S 0,1,4,24,192,9472,1182208,135668736,14993473536,1702145425408,

%T 212302947942400,32402586267549696,6715751146400514048,

%U 1845064263947813650432,597912413872386432040960

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

%t With[{nn=30},Take[CoefficientList[Series[Tanh[Tan[x]]*Tan[x]/2,{x,0,nn}],x] Range[ 0,nn]!,{1,-1,2}]] (* _Harvey P. Dale_, Jan 30 2023 *)

%Y A009812.

%K nonn

%O 0,3

%A _R. H. Hardin_

%E Extended and signs tested 03/97.

%E Previous Mathematica program replaced by _Harvey P. Dale_, Jan 30 2023