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 A306602 #14 Mar 08 2019 23:59:00
%S A306602 120,720,1200,120,120,1200,720,120,120,720,720,120,120,720,720,120,
%T A306602 120,720,720,120,120,720,720,120,120,720,1200,120,120,1200,720,120,
%U A306602 120,720,1200,600,600,1200,720,120
%N A306602 Number of elements in the ten nonconvex regular 4-polytopes (regular 4-dimensional star-polytopes), as a four-column array, read by rows, with rows ordered first by increasing density, then by increasing cell-count, then by increasing face-count, then by increasing edge-count and then by increasing vertex-count.
%C A306602 Only included for completeness (see other sequences in crossrefs). This is one of those entries that I think should be included since it is such an elementary sequence in geometry, but where the terms do otherwise not really make a very spectacular sequence.
%C A306602 The ordering of the polytopes in the enumeration of the element counts is somewhat arbitrary, though based on invariants inherently associated with these polytopes. For example, ordering first by vertex-count, then by edge-count, then by face-count and then by cell-count might have been as good a choice as the one used for the sequence.
%H A306602 Wikipedia, <a href="https://en.wikipedia.org/wiki/Regular_4-polytope#Regular_star_.28Schl.C3.A4fli.E2.80.93Hess.29_4-polytopes">Regular 4-polytope - Regular star (Schläfli-Hess) 4-polytopes</a>
%e A306602 Polytope | Schläfli symbol | Density | Cells | Faces | Edges | Vertices
%e A306602 ----------------------------------------------------------------------------------
%e A306602 Sm st 120-cell | {5/2,5,3} | 4 | 120 | 720 | 1200 | 120
%e A306602 Ico 120-cell | {3,5,5/2} | 4 | 120 | 1200 | 720 | 120
%e A306602 Grt 120-cell | {5,5/2,5} | 6 | 120 | 720 | 720 | 120
%e A306602 Grd 120-cell | {5,3,5/2} | 20 | 120 | 720 | 720 | 120
%e A306602 Grt st 120-cell | {5/2,3,5} | 20 | 120 | 720 | 720 | 120
%e A306602 Grd st 120-cell | {5/2,5,5/2} | 66 | 120 | 720 | 720 | 120
%e A306602 Grt grd 120-cell | {5,5/2,3} | 76 | 120 | 720 | 1200 | 120
%e A306602 Grt ico 120-cell | {3,5/2,5} | 76 | 120 | 1200 | 720 | 120
%e A306602 Grt grd st 120-cell | {5/2,3,3} | 191 | 120 | 720 | 1200 | 600
%e A306602 Grd 600-cell | {3,3,5/2} | 191 | 600 | 1200 | 720 | 120
%e A306602 ======================
%e A306602 | Keys |
%e A306602 ======================
%e A306602 | Sm | Small |
%e A306602 | St | Stellated |
%e A306602 | Grt | Great |
%e A306602 | Grd | Grand |
%e A306602 | Ico | Icosahedral |
%e A306602 ======================
%Y A306602 Cf. A048789, A063924, A063925, A063926, A063927.
%K A306602 nonn,tabf,fini,full
%O A306602 1,1
%A A306602 _Felix Fröhlich_, Feb 27 2019