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 A071907 #21 Mar 05 2020 23:56:19
%S A071907 1,4,4,4,4,1,1,1,1,4,4,4,4,1,1,1,1,4,1,4,1,4,4,4,4,1,1,1,1,4,4,4,4,1,
%T A071907 1,1,1,4,1,4,1,4,4,4,4,1,4,4,4,4,1,4,4,4,4,1,1,1,1,4,4,4,4,1,1,1,1,4,
%U A071907 1,4,1,4,4,4,4,1,1,1,1,4,4,4,4,1,1,1,1,4,1,4,1,4,4,4,4,1,4,4,4,4,1,4,4,4,4
%N A071907 Kolakoski-(1,4) sequence: a(n) is length of n-th run.
%C A071907 1444411, 14444111144441111414144441111 are primes. - _Vincenzo Librandi_, Mar 02 2016
%H A071907 Ivan Neretin, <a href="/A071907/b071907.txt">Table of n, a(n) for n = 1..10000</a>
%H A071907 Michael Baake and Bernd Sing, <a href="http://arXiv.org/abs/math.MG/0206098">Kolakoski-(3,1) is a (deformed) model set</a>, arXiv:math/0206098 [math.MG], 2002-2003.
%H A071907 Rémy Sigrist, <a href="/A071907/a071907.png">Scatterplot of twice the number of ones among the first n terms of the sequence minus n for n = 1..1000000</a>
%t A071907 seed = {1, 4}; w = {}; i = 1; Do[w = Join[w,Array[seed[[Mod[i - 1, Length[seed]] + 1]] &, If[i > Length[w], seed, w][[i]]]]; i++, {n, 42}]; w (* _Ivan Neretin_, Apr 02 2015 *)
%Y A071907 Cf. A000002, A071820, A064353, A071928, A071942.
%K A071907 nonn,easy
%O A071907 1,2
%A A071907 _N. J. A. Sloane_