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 A270665 #4 Mar 21 2016 07:18:24
%S A270665 1,1,4,20,136,1016,10112,102080,1259648,16501888,243214592,3792156928,
%T A270665 66314635264,1201731751936,23824296632320,496708324364288,
%U A270665 11065302289285120,257749924759273472,6397599337673523200,165009476729535463424,4496775223731602063360
%N A270665 E.g.f.: Product_{k>=1} 1/(1 - tan(x^k)).
%t A270665 nmax = 25; Range[0, nmax]! * CoefficientList[Series[Product[1/(1-Tan[x^k]), {k, 1, nmax}], {x, 0, nmax}], x]
%Y A270665 Cf. A203716, A218504, A270664, A270666.
%K A270665 nonn
%O A270665 0,3
%A A270665 _Vaclav Kotesovec_, Mar 21 2016