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 A273509 #6 May 25 2016 10:25:36 %S A273509 120,384,384,1152,14400,14400 %N A273509 Orders of the symmetry groups of the six convex regular 4-polytopes, in the order 5-cell, 8-cell, 16-cell, 24-cell, 120-cell, 600-cell. %H A273509 Wikipedia, <a href="http://en.wikipedia.org/wiki/Regular_4-polytope#Properties">Regular 4-polytope</a> (see table in section "Properties"). %Y A273509 Cf. A098427. %K A273509 nonn,fini,full %O A273509 1,1 %A A273509 _Felix Fröhlich_, May 23 2016