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 A023630 #3 Mar 30 2012 18:55:53 %S A023630 3,2,4,4,2,2,4,2,2,4,4,4,2,2,4,4,4,2,2,4,2,2,4,2,2,4,4,4,2,2,4,2,2,4, %T A023630 2,2,4,4,4,2,2,4,4,4,2,2,4,4,4,2,2,4,2,2,4,2,2,4,4,4,2,2,4,4,4,2,2,4, %U A023630 4,4,2,2,4,2,2,4,2,2,4,4,4,2,2,4,2,2,4,2,2,4,4,4,2,2,4,2,2,4,2 %N A023630 a(n) = s(2n) - s(2n-1), where s( ) is sequence A023629. %K A023630 nonn %O A023630 1,1 %A A023630 _Clark Kimberling_