A012823 - OEIS

%I #6 Nov 04 2024 12:19:27

%S 1,3,53,1855,156425,19537595,3987121981,1087120051511,408148372272017,

%T 193531749818796403,116081047496759766725,84538055378229508493871,

%U 74205177566923695709271961

%N arcsin(sec(x)*arcsinh(x))=x+3/3!*x^3+53/5!*x^5+1855/7!*x^7...

%t With[{nn=30},Take[CoefficientList[Series[ArcSin[Sec[x]ArcSinh[x]],{x,0,nn}],x] Range[0,nn-1]!,{2,-1,2}]] (* _Harvey P. Dale_, Nov 04 2024 *)

%K nonn

%O 0,2

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