%I #6 Nov 28 2016 19:49:16
%S 0,2,-12,-2,10248,-672678,-20843460,16777261590,-2958597356400,
%T -195442688499150,352062527506877700,-110808084056350289490,
%U -28855116263423436192360,55915766816627672060266890
%N arctan(arcsinh(x)*arctan(x))=2/2!*x^2-12/4!*x^4-2/6!*x^6+10248/8!*x^8...
%t With[{nn=30},Take[CoefficientList[Series[ArcTan[ArcSinh[x]*ArcTan[x]],{x,0,nn}],x] Range[0,nn]!,{1,-1,2}]] (* _Ray Chandler_, Nov 28 2016 *)
%K sign
%O 0,2
%A Patrick Demichel (patrick.demichel(AT)hp.com)