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 A009392 #12 Jun 22 2015 22:29:00
%S A009392 0,1,-1,-3,8,25,-121,-427,3128,12465,-124921,-555731,7158128,35135945,
%T A009392 -557749921,-2990414715,56767019408,329655706465,-7316056402321,
%U A009392 -45692713833379,1164842760597368,7777794952988025,-224574978081433321
%N A009392 Expansion of e.g.f.: log(1+tanh(x))/cosh(x).
%t A009392 With[{nn=30},CoefficientList[Series[Log[1+Tanh[x]]/Cosh[x],{x,0,nn}],x] Range[ 0,nn]!] (* _Harvey P. Dale_, Oct 06 2014 *)
%K A009392 sign,easy
%O A009392 0,4
%A A009392 _R. H. Hardin_
%E A009392 Extended with signs by _Olivier Gérard_, Mar 15 1997
%E A009392 Definition clarified and prior Mathematica program replaced by _Harvey P. Dale_, Oct 06 2014