%I #6 May 24 2013 12:11:43
%S 1,0,20,-784,26256,-4466176,435729216,-104111460608,23261262303488,
%T -7794968497086464,2988775301503636480,-1434421552426973564928,
%U 811112609409475303936000,-540598484103424258178285568
%N sin(sec(x)*arctan(x))=x+20/5!*x^5-784/7!*x^7+26256/9!*x^9...
%t With[{nn=30},Take[CoefficientList[Series[Sin[Sec[x]ArcTan[x]],{x,0,nn}],x] Range[0,nn-1]!,{2,-1,2}]] (* _Harvey P. Dale_, May 24 2013 *)
%K sign
%O 0,3
%A Patrick Demichel (patrick.demichel(AT)hp.com)