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 A279647 #19 Nov 01 2021 03:14:21 %S A279647 0,0,0,1,2,4,0,2,3,4,5,6,7,9,10,0,3,4,5,6,7,9,10,11,12,13,14,15,16,17, %T A279647 18,20,0,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,20,21,22,23,24,25,26, %U A279647 27,28,29,30,31,32,33,34 %N A279647 Irregular triangle read by rows: possible numbers of the diagonals of an n-faced convex polyhedron. %e A279647 Triangle begins: %e A279647 4 | 0; %e A279647 5 | 0; %e A279647 6 | 0, 1, 2, 4; %e A279647 7 | 0, 2, 3, 4, 5, 6, 7, 9, 10; %e A279647 8 | 0, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 20; %Y A279647 Cf. A279015, A279019, A279022, A279620, A279679, A279681. %K A279647 nonn,tabf,more %O A279647 4,5 %A A279647 _Vladimir Letsko_, Dec 16 2016