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 A044878 #5 Mar 30 2012 18:56:47 %S A044878 344,345,346,347,348,349,351,359,367,375,383,391,393,394,395,396,397, %T A044878 398,406,407,409,410,411,412,413,414,415,417,418,419,420,421,422,423, %U A044878 425,426,427,428,429,430,431,433,434,435,436 %N A044878 Numbers having, in base 7, (sum of even run lengths)=(sum of odd run lengths). %K A044878 nonn,base %O A044878 1,1 %A A044878 _Clark Kimberling_