A012442 - OEIS

%I #6 Aug 10 2024 15:49:56

%S 1,0,12,-120,17808,-962880,219945792,-31053369984,10719320103168,

%T -2908608708409344,1441051026777725952,-637493975166202091520,

%U 433239709928964325478400,-282573293205848764594176000

%N sec(arctan(x)*arcsin(x))=1+12/4!*x^4-120/6!*x^6+17808/8!*x^8...

%t With[{nn=30},Take[CoefficientList[Series[Sec[ArcTan[x]ArcSin[x]],{x,0,nn}],x] Range[0,nn]!,{1,-1,2}]] (* _Harvey P. Dale_, Aug 10 2024 *)

%K sign

%O 0,3

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