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 A131783 #6 Mar 04 2022 01:25:55 %S A131783 1,4,2,8,6,3,13,11,8,4,19,17,14,10,5,26,24,21,17,12,6,34,32,29,25,20, %T A131783 14,7,43,41,38,34,29,23,16,8,53,51,48,44,39,33,26,18,9,64,62,59,55,50, %U A131783 44,37,29,20,10 %N A131783 A000012 * (A004736 + A002260 - I). %C A131783 Left column = A034856: (1, 4, 8, 13, 19, ...). %C A131783 Row sums = A084990: (1, 6, 17, 36, 65, 106, ...). %F A131783 A000012 * (A004736 + A002260 - I), I = Identity matrix; A004736 = (1; 2,1; 3,2,1; ...); A002260 = (1; 1,2; 1,2,3; ...). %e A131783 First few rows of the triangle: %e A131783 1; %e A131783 4, 2; %e A131783 8, 6, 3; %e A131783 13, 11, 8, 4; %e A131783 19, 17, 14, 10, 5; %e A131783 26, 24, 21, 17, 12, 6; %e A131783 34, 32, 29, 25, 20, 14, 7; %e A131783 ... %Y A131783 Cf. A004736, A002260, A034856, A084990. %K A131783 nonn,tabl %O A131783 1,2 %A A131783 _Gary W. Adamson_, Jul 14 2007