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 A026256 #4 Mar 30 2012 18:56:05 %S A026256 1,1,1,1,2,3,2,3,3,4,3,4,5,4,6,4,6,5,7,8,6,8,6,9,10,7,10,8,11,8,11,12, %T A026256 9,13,10,13,10,14,15,11,15,11,16,12,16,17,13,18,13,18,19,14,20,15,20, %U A026256 15,21,22,16,22,16,23,17,23,24,18,25,18,25,19 %N A026256 a(n) = |s(n) - n|, where s = A026255. %K A026256 nonn %O A026256 1,5 %A A026256 _Clark Kimberling_