A013303 - OEIS

%I #6 May 15 2018 17:53:27

%S 1,0,3,90,5145,472500,63877275,11947285350,2955047720625,

%T 934039255149000,367306824871861875,175873128591661751250,

%U 100738594342264429175625,68014527663768884135437500

%N sec(log(x+1)-arctanh(x))=1+3/4!*x^4+90/6!*x^6+5145/8!*x^8...

%t With[{nn=30},Take[CoefficientList[Series[Sec[Log[x+1]-ArcTanh[x]],{x,0,nn}],x] Range[0,nn]!,{1,-1,2}]] (* _Harvey P. Dale_, May 15 2018 *)

%K nonn

%O 0,3

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