This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A012462 #13 Jan 09 2024 13:20:30
%S A012462 0,2,-16,248,-3456,-164448,17537280,5001348480,-3047690956800,
%T A012462 999150768960000,-194340969261158400,-28292890791044597760,
%U A012462 48811395838790000148480,-15658656394130132870062080,-19215487887156327014813859840,37972554002174500707798919249920
%N A012462 Arcsinh(arctan(x)^2) = 2/2!*x^2 - 16/4!*x^4 + 248/6!*x^6 - 3456/8!*x^8 + ...
%t A012462 With[{nn=30},Take[CoefficientList[Series[ArcSinh[ArcTan[x]^2],{x,0,nn}],x] Range[0,nn]!,{1,-1,2}]] (* _Harvey P. Dale_, May 06 2013 *)
%K A012462 sign
%O A012462 0,2
%A A012462 Patrick Demichel (patrick.demichel(AT)hp.com)
%E A012462 Definition clarified by _Harvey P. Dale_, May 06 2013