A012062 - OEIS

%I #6 Sep 15 2013 13:29:08

%S 1,-1,1,-1,449,45119,6456385,1205597119,290952557185,88525830844799,

%T 33241403103347585,15120239602445366399,8199386238595549354561,

%U 5228782379279703730965439,3875091407041220683147290049

%N sech(sin(arctanh(x)))=1-1/2!*x^2+1/4!*x^4-1/6!*x^6+449/8!*x^8...

%t With[{nn=30},Take[CoefficientList[Series[Sech[Sin[ArcTanh[x]]],{x,0,nn}],x] Range[0,nn]!,{1,-1,2}]] (* _Harvey P. Dale_, Sep 15 2013 *)

%K sign

%O 0,5

%A Patrick Demichel (patrick.demichel(AT)hp.com)