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 A287179 #5 May 23 2017 14:31:38 %S A287179 1,1,0,1,1,0,2,0,1,0,1,1,0,1,1,0,2,0,1,0,2,0,2,0,1,0,1,1,0,2,0,1,0,1, %T A287179 1,0,1,1,0,2,0,1,0,1,1,0,1,1,0,2,0,1,0,2,0,2,0,1,0,1,1,0,2,0,1,0,2,0, %U A287179 2,0,1,0,2,0,2,0,1,0,1,1,0,2,0,1,0,1 %N A287179 1-limiting word of the morphism 0->10, 1->20, 2->1. %C A287179 Starting with 0, the first 5 iterations of the morphism yield words shown here: %C A287179 1st: 10 %C A287179 2nd: 2010 %C A287179 3rd: 1102010 %C A287179 4th: 2020101102010 %C A287179 5th: 11011020102020101102010 %C A287179 The 1-limiting word is the limit of the words for which the number of iterations is odd. %C A287179 Let U, V, W be the limits of u(n)/n, v(n)/n, w(n)/n, respectively. Then 1/U + 1/V + 1/W = 1, where %C A287179 U = 2.246979603717467061050009768008..., %C A287179 V = 2.801937735804838252472204639014..., %C A287179 W = 5.048917339522305313522214407023... %C A287179 If n >=2, then u(n) - u(n-1) is in {2,3}, v(n) - v(n-1) is in {1,2,4,6}, and w(n) - w(n-1) is in {2,4,7,10}. %H A287179 Clark Kimberling, <a href="/A287179/b287179.txt">Table of n, a(n) for n = 1..10000</a> %e A287179 1st iterate: 10 %e A287179 3rd iterate: 1102010 %e A287179 5th iterate: 110110201020201011020100 %t A287179 s = Nest[Flatten[# /. {0 -> {1, 0}, 1 -> {2, 0}, 2 -> 1}] &, {0}, 9] (* A287179 *) %t A287179 Flatten[Position[s, 0]] (* A287180 *) %t A287179 Flatten[Position[s, 1]] (* A287181 *) %t A287179 Flatten[Position[s, 2]] (* A287182 *) %Y A287179 Cf. A287121, A287180, A287181, A287182. %K A287179 nonn,easy %O A287179 1,7 %A A287179 _Clark Kimberling_, May 22 2017