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 A308875 #12 Jul 20 2019 12:45:53 %S A308875 4,6,8,12,20,5,8,16,24,120,600,6,10,32,7,12,64,8,14,128,9,16,256,10, %T A308875 18,512,11,20,1024,12,22,2048,13,24,4096,14,26,8192,15,28,16384,16,30, %U A308875 32768,17,32,65536,18,34,131072,19,36,262144,20,38,524288,21,40,1048576 %N A308875 Irregular table read by rows: the n-th row lists the number of (n-1)-dimensional cells in the convex regular n-dimensional polytopes in ascending order, n >= 3. %C A308875 Also, the n-th row lists the number of edges (i.e., 1-dimensional cells) in the convex regular n-dimensional polytopes in ascending order. - _Jianing Song_, Jun 29 2019 %H A308875 Wikipedia, <a href="https://en.wikipedia.org/wiki/List_of_regular_polytopes_and_compounds">List of regular polytopes and compounds</a> %F A308875 For n >= 5, the n-th row is n+1, 2n, 2^n. - _Jianing Song_, Jun 29 2019 %e A308875 From _Jianing Song_, Jun 29 2019: (Start) %e A308875 Row 3: 4, 6, 8, 12, 20; %e A308875 Row 4: 5, 8, 16, 24, 120, 600; %e A308875 Row 5: 6, 10, 32; %e A308875 Row 6: 7, 12, 64; %e A308875 ... %e A308875 (End) %o A308875 (PARI) row(n) = if(n>=5, [n+1, 2*n, 2^n], if(n==3, [4, 6, 8, 12, 20], if(n==4, [5, 8, 16, 24, 120, 600]))) %o A308875 list(n) = my(v=[]); for(i=3, n, v=concat(v, row(i))); v \\ _Jianing Song_, Jun 29 2019 %Y A308875 Cf. A000079, A005843, A053016 (row 3), A063924 (row 4). %K A308875 nonn,easy,tabf %O A308875 3,1 %A A308875 _Donghwi Park_, Jun 29 2019 %E A308875 Edited by _Jianing Song_, Jun 29 2019