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 A140737 #7 Nov 14 2023 04:43:42 %S A140737 1,1,1,1,1,2,3,1,1,1,3,6,4,5,1,1,1,4,10,10,15,6,7,1,1,1,5,15,20,35,21, %T A140737 28,8,9,1,1,1,6,21,35,70,56,84,36,45,10,11,1,1,1,7,28,56,126,126,210, %U A140737 120,165,55,66,12,13,1,1 %N A140737 Triangle read by rows, X^n * [1,0,0,0,...]; where X = an infinite tridiagonal matrix with (1,1,1,...) in the main and subdiagonals and (1,0,1,0,1,...) in the subsubdiagonal. %e A140737 First few rows of the triangle are: %e A140737 1; %e A140737 1, 1, 1; %e A140737 1, 2, 3, 1, 1; %e A140737 1, 3, 6, 4, 5, 1, 1; %e A140737 1, 4, 10, 10, 15, 6, 7, 1, 1; %e A140737 1, 5, 15, 20, 35, 21, 28, 8, 9, 1, 1; %e A140737 1, 6, 21, 35, 70, 56, 84, 36, 45, 10, 11, 1, 1; %e A140737 1, 7, 28, 56, 126, 126, 210, 120, 165, 55, 66, 12, 13, 1, 1; %e A140737 ... %Y A140737 Cf. A140736 (reversed rows), A001906 (row sums). %K A140737 nonn,tabf %O A140737 1,6 %A A140737 _Gary W. Adamson_ and _Roger L. Bagula_, May 25 2008