%I #6 Jul 04 2019 12:54:41
%S 1,0,12,-120,15120,-1003200,175323456,-30612097152,8428742150400,
%T -2694273274447872,1128666024421563392,-559638290295925823488,
%U 336992041752644836265984,-237186459370976230365020160
%N sec(sinh(x)*arctan(x))=1+12/4!*x^4-120/6!*x^6+15120/8!*x^8...
%t With[{nn=30},Take[CoefficientList[Series[Sec[Sinh[x]ArcTan[x]],{x,0,nn}],x] Range[0,nn]!,{1,-1,2}]] (* _Harvey P. Dale_, Jul 04 2019 *)
%K sign
%O 0,3
%A Patrick Demichel (patrick.demichel(AT)hp.com)