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 A009568 #19 Jan 22 2018 02:39:10
%S A009568 0,1,-1,4,-16,91,-616,4894,-44416,453541,-5145856,64222984,-874402816,
%T A009568 12897183391,-204862698496,3486535686274,-63292764553216,
%U A009568 1220795601029641,-24931903045697536,537463528325234764,-12196043454064623616,290588368323926512291,-7253387436695186046976
%N A009568 Expansion of e.g.f.: sinh(log(1+sinh(x))).
%H A009568 G. C. Greubel, <a href="/A009568/b009568.txt">Table of n, a(n) for n = 0..438</a>
%F A009568 a(2*n) = A006154(2*n)/2, n>0. - _Ralf Stephan_, Apr 29 2004
%t A009568 With[{nn=20},CoefficientList[Series[Sinh[Log[1+Sinh[x]]],{x,0,nn}],x] Range[0,nn]!] (* _Harvey P. Dale_, Dec 08 2017 *)
%o A009568 (PARI) x='x+O('x^30); concat([0], Vec(serlaplace( sinh(log(1+sinh(x)))))) \\ _G. C. Greubel_, Jan 21 2018
%K A009568 sign,easy
%O A009568 0,4
%A A009568 _R. H. Hardin_
%E A009568 Extended with signs by _Olivier Gérard_, Mar 15 1997
%E A009568 Prior Mathematica program replaced and definition clarified by _Harvey P. Dale_, Dec 08 2017
%E A009568 Terms a(20) to a(22) added by _G. C. Greubel_, Jan 21 2018