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 A009241 #14 Apr 05 2022 13:16:45
%S A009241 1,1,1,1,1,-7,-47,-55,449,2897,18209,5105,-1441087,-7252983,41192817,
%T A009241 341550201,2660018305,43255573537,-460752070079,-11238852308639,
%U A009241 21450325749889,963068748879257,1057483104728337,153386988236833449
%N A009241 Expansion of e.g.f.: exp(tan(tanh(x))).
%t A009241 With[{nn=30},CoefficientList[Series[Exp[Tan[Tanh[x]]],{x,0,nn}],x] Range[ 0,nn]!] (* _Harvey P. Dale_, Apr 05 2022 *)
%K A009241 sign,easy
%O A009241 0,6
%A A009241 _R. H. Hardin_
%E A009241 Extended with signs by _Olivier Gérard_, Mar 15 1997
%E A009241 Definition clarified and prior Mathematica program replaced by _Harvey P. Dale_, Apr 05 2022