%I #6 Oct 07 2016 17:56:50
%S 1,0,-12,480,-27888,2353920,-274245312,41974872576,-8068087373568,
%T 1860842339721216,-486190504963034112,129225947748233994240,
%U -22917287813817561968640,-13673939410058068058112000
%N cos(arctan(x)^2)=1-12/4!*x^4+480/6!*x^6-27888/8!*x^8...
%t With[{nn=30},Take[CoefficientList[Series[Cos[ArcTan[x]^2],{x,0,nn}],x] Range[0,nn]!,{1,-1,2}]] (* _Harvey P. Dale_, Oct 07 2016 *)
%K sign
%O 0,3
%A Patrick Demichel (patrick.demichel(AT)hp.com)
%E Definition clarified by _Harvey P. Dale_, Oct 07 2016