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 A023661 #3 Mar 30 2012 18:55:53 %S A023661 0,1,4,8,13,20,29,40,53,67,82,99,118,139,162,187,214,243,274,306,339, %T A023661 374,411,450,491,534,579,626,675,726,779,834,891,950,1010,1071,1134, %U A023661 1199,1266,1335,1406,1479,1554,1631,1710,1791,1874,1959,2046 %N A023661 Convolution of odd numbers and A014306. %K A023661 nonn %O A023661 1,3 %A A023661 _Clark Kimberling_