%I #6 Nov 29 2016 10:57:15
%S 0,3,23,721,25199,1716121,141920855,20103619537,4016386229855,
%T 1241116799607721,494609567396520071,244232906612554953633,
%U 140315440295583485315151,92810530303082004433849401
%N -arctan(sin(x)-arctanh(x))=3/3!*x^3+23/5!*x^5+721/7!*x^7+25199/9!*x^9...
%t With[{nn=30},Take[CoefficientList[Series[-ArcTan[Sin[x]-ArcTanh[x]],{x,0,nn}],x] Range[0,nn-1]!,{2,-1,2}]] (* _Ray Chandler_, Nov 29 2016 *)
%K nonn
%O 0,2
%A Patrick Demichel (patrick.demichel(AT)hp.com)