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 A131252 #7 Feb 18 2022 22:42:33 %S A131252 1,2,1,4,3,1,7,6,3,1,12,11,7,3,1,20,19,14,7,3,1,33,32,26,15,7,3,1,54, %T A131252 53,46,30,15,7,3,1,88,87,79,57,31,15,7,3,1,143,142,133,104,62,31,15,7, %U A131252 3,1 %N A131252 A052509 * A000012. %C A131252 Left border = A000071, Fibonacci numbers - 1, starting with F(3): (1, 2, 4, 7, 12, ...). Row sums = A131253: (1, 3, 8, 17, 34, 64, 117, ...). %F A131252 A052509 * A000012, where A000012 = (1; 1,1; 1,1,1; ...). %e A131252 First few rows of the triangle: %e A131252 1; %e A131252 2, 1; %e A131252 4, 3, 1; %e A131252 7, 6, 3, 1; %e A131252 12, 11, 7, 3, 1; %e A131252 20, 19, 14, 7, 3, 1; %e A131252 33, 32, 26, 15, 7, 3, 1; %e A131252 ... %Y A131252 Cf. A000071, A000012, A052509, A131253. %K A131252 nonn,tabl %O A131252 0,2 %A A131252 _Gary W. Adamson_, Jun 23 2007