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 A133418 #11 Jul 04 2013 13:11:30 %S A133418 0,2,2,1,0,0,2,1,1,0,2,3,3,2,2,2,2,1,2,2,3,1,1,4,3,3,1,4,4,3,3,1,1,4, %T A133418 3,3,1,4,4,3,1,2,2,3,1,1,2,3,3,1,1,2,2,3,1,1,2,3,3,1,1,2,2,3,1,1,2,3, %U A133418 3,1,2,3,3,4,4,4,3,4,4,4,3,1,1,4,3,3,1,4,4,3,3,1,1,4,3,3,1,4,4,3,4,3,3,3,3 %N A133418 Let l(n) = number of letters in n, A005589(n). If l(n) = 4 set a(n) = 0; otherwise a(n) = a(l(n)) + 1. %C A133418 Based on the observation by Diane Karloff (see A005589) that the trajectory of l always converges to 4. %C A133418 The smallest n with a(n) = 6 is 1103323373373373373373373373373 (one nonillion one hundred and three octillion ...) which has 323 letters. %H A133418 R. J. Mathar, <a href="/A133418/b133418.txt">Table of n, a(n) for n = 0..11999</a> %H A133418 R. J. Mathar, <a href="/A133418/a133418.txt">Maple program to make b-file</a> %e A133418 5 has four letters so a(5) = 0. 3 has five letters so a(3) = a(5) + 1 = 1. %Y A133418 A variant of A016037. %K A133418 nonn,word,easy %O A133418 0,2 %A A133418 _N. J. A. Sloane_, Nov 27 2007