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 A131049 #4 Feb 21 2022 00:23:26 %S A131049 1,2,2,7,6,3,20,28,12,4,61,100,70,20,5,182,366,300,140,30,6,547,1274, %T A131049 1281,700,245,42,7,1640,4376,5096,3416,1400,392,56,8,4921,14760,19692, %U A131049 15288,7686,2520,588,72,9 %N A131049 (1/4) * (A007318^3 - A007318^(-1)). %C A131049 Row sums = powers of 4: (1, 4, 16, 64, ...). %C A131049 Left border = A015518: (1, 2, 7, 20, 61, 182, ...). %F A131049 (1/4) * (P^3 - 1/P), where P = Pascal's triangle, A007318. Delete right border of zeros. %e A131049 First few rows of the triangle: %e A131049 1; %e A131049 2, 2; %e A131049 7, 6, 3; %e A131049 20, 28, 12, 4; %e A131049 61, 100, 70, 20, 5; %e A131049 182, 366, 300, 140, 30, 6; %e A131049 547, 1274, 1281, 700, 245, 42, 7; %e A131049 ... %Y A131049 Cf. A015518, A007318, A131047, A131048, A131050, A131051. %K A131049 nonn,tabl %O A131049 1,2 %A A131049 _Gary W. Adamson_, Jun 12 2007