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 A131303 #5 Mar 03 2022 23:48:52 %S A131303 1,3,1,5,5,1,7,3,3,1,9,15,5,3,1,11,13,7,5,3,1,13,11,11,9,5,3,115,7,9, %T A131303 7,9,5,3,1,17,9,13,11,11,11,5,3,1,19,43,15,13,7,7,7,5,3,1 %N A131303 2*A122204(deleting the right border of zeros) - A000012. %e A131303 First few rows of the triangle: %e A131303 1; %e A131303 3, 1; %e A131303 5, 5, 1; %e A131303 7, 3, 3, 1; %e A131303 9, 15, 5, 3, 1; %e A131303 11, 13, 7, 5, 3, 1; %e A131303 13, 11, 11, 9, 5, 3, 1; %e A131303 ... %Y A131303 Cf. A122204, A000012, A122203, A131302. %K A131303 nonn,tabl %O A131303 1,2 %A A131303 _Gary W. Adamson_, Jun 27 2007