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 A044292 #5 Mar 30 2012 18:56:43 %S A044292 41,122,203,284,365,369,446,527,608,689,770,851,932,1013,1094,1098, %T A044292 1175,1256,1337,1418,1499,1580,1661,1742,1823,1827,1904,1985,2066, %U A044292 2147,2228,2309,2390,2471,2552,2556,2633,2714,2795 %N A044292 Numbers n such that string 4,5 occurs in the base 9 representation of n but not of n-1. %K A044292 nonn,base %O A044292 1,1 %A A044292 _Clark Kimberling_