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 A131305 #4 Mar 03 2022 23:49:57 %S A131305 1,3,1,5,5,1,7,3,3,1,9,15,5,3,1,11,13,7,5,3,1,13,11,11,9,5,3,1,15,7,9, %T A131305 7,9,5,3,1,17,9,13,11,11,11,5,3,1,19,43,15,13,7,9,11,5,3,1 %N A131305 2*A122288 - A000012. %F A131305 2*A122288(deleting the right border of zeros) - A000012. %e A131305 First few rows of the triangle: %e A131305 1; %e A131305 3, 1; %e A131305 5, 5, 1; %e A131305 7, 3, 3, 1; %e A131305 9, 15, 5, 3, 1; %e A131305 11, 13, 7, 5, 3, 1; %e A131305 13, 11, 11, 9, 5, 3, 1; %e A131305 ... %Y A131305 Cf. A122288, A122203, A131302, A131303, A131304. %K A131305 nonn,tabl %O A131305 0,2 %A A131305 _Gary W. Adamson_, Jun 27 2007