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 A113138 #10 Feb 08 2017 22:07:13 %S A113138 1,3,4,5,1,2,3,4,1,2,3,4,5,1,3,4,1,2,3,1,2,3,4,1,3,4,1,2,3,1,2,3,4,1, %T A113138 2,3,4,5,1,3,4,5,1,2,3,4,1,3,4,1,2,3,1,3,4,1,2,3,1,2,3,4,1,3,4,5,1,2, %U A113138 3,4,1,3,4,1,2,3,1,3,4,1,2,3,1,2,3,4,1 %N A113138 Self-describing sequence made of strings of consecutive integers. The number of elements in each string is the sequence itself. %C A113138 The less interesting sequence 1,1,1,1,1,1,1,1, ... obeys the same rule. %H A113138 Rémy Sigrist, <a href="/A113138/b113138.txt">Table of n, a(n) for n = 1..1000</a> %H A113138 Rémy Sigrist, <a href="/A113138/a113138.gp.txt">PARI program for A113138</a> %e A113138 First string is "1", having 1 element. Second string is "3,4,5" having 3 elements. Third string is "1,2,3,4" which has 4 elements. Next string is "1,2,3,4,5", made of 5 elements. Next string is "1", having only 1 element, etc. So we have 1 element, then 3, then 4, then 5, then 1, etc. This is the sequence itself. %Y A113138 Cf. A281579. %K A113138 easy,nonn,nice %O A113138 1,2 %A A113138 _Eric Angelini_, Jan 04 2006 %E A113138 More terms from _Rémy Sigrist_, Feb 08 2017