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 A030581 #4 Mar 30 2012 18:56:18 %S A030581 1,1,1,1,1,0,1,2,3,3,4,4,5,5,6,6,7,6,6,7,7,7,7,7,7,7,7,7,7,6,6,7,7,7, %T A030581 7,7,7,7,7,7,7,6,6,7,7,7,7,7,7,7,7,7,7,6,6,7,7,7,7,7,7,7,7,7,7,6,5,6, %U A030581 7,6,7,7,6,7,7,6,7,7,6,7,7,6,7,6,7,8,9,10,11 %N A030581 a(n)=(# 1's)-(# 0's) in first n terms of A030567. %K A030581 nonn %O A030581 1,8 %A A030581 _Clark Kimberling_