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 A102072 #9 Aug 15 2016 10:06:26
%S A102072 1,1,1,25,-415,35825,-3356575,492769225,-96314333375,24701457990625,
%T A102072 -8006683308349375,3204344303824405625,-1551453429875871169375,
%U A102072 893896220277392770140625,-604413346665043743464609375
%N A102072 E.g.f. sec(arcsinh(x)) = cosec(arccosh(x)) (even powers only).
%e A102072 sec(arcsinh(x)) = 1 + x^2/2 + x^4/4! + 25x^6/6! - 415x^8/8! +...
%e A102072 sech(arcsin(x)) = 1 - x^2/2 + x^4/4! - 25x^6/6! - 415x^8/8! -...
%t A102072 With[{nn=30},Take[CoefficientList[Series[Sec[ArcSinh[x]],{x,0,nn}],x] Range[0,nn]!,{1,-1,2}]] (* _Harvey P. Dale_, Aug 15 2016 *)
%K A102072 sign
%O A102072 0,4
%A A102072 _Ralf Stephan_, Dec 31 2004