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 A121560 #5 Mar 30 2012 18:39:58 %S A121560 2,1,1,3,1,3,1,3,2,2,1,2,2,3,1,3,2,2,2,2,1,2,2,3,1,2,2,3,2,2,2,1,2,3, %T A121560 1,3,1,3,2,1,1,3,2,3,2,2,1,2,1,1,2,1,2,2,2,2,3,2,2,2,2,1,2,1,1,2,1,3, %U A121560 1,2,1,1,4,2,1,1,4,3,1,3,2,2,1,2,1,1,2,2,2,2,2,2,2,1,2,2,3,1,2,1,1,2,2,1,1 %N A121560 Lengths of blocks of zeros in sequence A121559. %H A121560 Kerry Mitchell, <a href="/A121560/b121560.txt">Table of n, a(n) for n = 1..2782</a> %e A121560 a(1) = 2 because A121559 begins 1, 0, 0, 1, with 2 zeros between 1's. %Y A121560 Cf. A121559. %K A121560 easy,nonn %O A121560 1,1 %A A121560 _Kerry Mitchell_, Aug 07 2006