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 A156710 #5 Dec 26 2023 12:30:09 %S A156710 1,1,1,1,3,1,1,3,6,6,1,3,6,18,16,1,3,6,18,48,44,1,3,6,18,48,132,120, %T A156710 136,18,48,132,360,328,1,3,6,18,48,132,360,984,896,1,3,6,18,48,132, %U A156710 360,984,2688,2448,1,3,6,18,48,132,360,984,2688,7344,6688 %N A156710 Triangle read by rows, A123191 * (A002605 * (A002605 * 0^(n-k))). %C A156710 Row sums = A002605: (1, 2, 6, 16, 44, 120,...) %C A156710 As a property of eigentriangles, sum of row terms = rightmost term of next row. %F A156710 Triangle read by rows, A123191 * (A002605 * (A002605 * 0^(n-k))). A123191 is %F A156710 unsigned, (A002605 * 0^(n-k))= an infinite lower triangular matrix with %F A156710 A002605 as the main diagonal prefaced with a 1: (1, 1, 2, 6, 16, 44,...) %F A156710 and the rest zeros. %e A156710 First few rows of the triangle = %e A156710 1; %e A156710 1, 1; %e A156710 1, 3, 2; %e A156710 1, 3, 6, 6; %e A156710 1, 3, 6, 18, 16; %e A156710 1, 3, 6, 18, 48, 44; %e A156710 1, 3, 6, 18, 48, 132, 120; %e A156710 1, 3, 6, 18, 48, 132, 360, 328; %e A156710 1, 3, 6, 18, 48, 132, 360, 984, 896; %e A156710 1, 3, 6, 18, 48, 132, 360, 984, 2688, 2448; %e A156710 1, 3, 6, 18, 48, 132, 360, 984, 2688, 7344, 6688; %e A156710 ... %Y A156710 Cf. A002605, A123191. %K A156710 nonn,tabl %O A156710 0,5 %A A156710 _Gary W. Adamson_, Feb 14 2009