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 A131302 #2 Mar 30 2012 17:25:21 %S A131302 1,3,1,5,5,1,7,3,3,1,9,13,5,3,1,11,15,7,5,3,1,13,11,11,9,5,3,1,15,9,9, %T A131302 7,9,5,3,1,17,7,13,11,11,11,5,3,1,19,33,15,13,7,9,11,5,3,1 %N A131302 2*A122203 - A000012. %F A131302 2*A122203(deleting the right border of zeros) - A000012. %e A131302 Row 4 = (7, 3, 3, 1) = 2*(4, 2, 2, 1) - (1, 1, 1, 1). First few rows of the triangle are: %e A131302 1; %e A131302 3, 1; %e A131302 5, 5, 1; %e A131302 7, 3, 3, 1; %e A131302 9, 13, 5, 3, 1; %e A131302 11, 15, 7, 5, 3, 1; %e A131302 13, 11, 11 9, 5, 3, 1; %e A131302 ... %Y A131302 Cf. A122203, A000012. %K A131302 nonn,tabl %O A131302 1,2 %A A131302 _Gary W. Adamson_, Jun 27 2007