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 A044135 #5 Mar 30 2012 18:56:42 %S A044135 33,69,105,141,177,198,213,249,285,321,357,393,414,429,465,501,537, %T A044135 573,609,630,645,681,717,753,789,825,846,861,897,933,969,1005,1041, %U A044135 1062,1077,1113,1149,1185,1188,1257,1278,1293,1329 %N A044135 Numbers n such that string 5,3 occurs in the base 6 representation of n but not of n-1. %K A044135 nonn,base %O A044135 1,1 %A A044135 _Clark Kimberling_