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 A269349 #14 Mar 03 2016 03:41:42
%S A269349 1,7,7,7,7,7,7,7,1,1,1,1,1,1,1,7,7,7,7,7,7,7,1,1,1,1,1,1,1,7,7,7,7,7,
%T A269349 7,7,1,1,1,1,1,1,1,7,7,7,7,7,7,7,1,7,1,7,1,7,1,7,7,7,7,7,7,7,1,1,1,1,
%U A269349 1,1,1,7,7,7,7,7,7,7,1,1,1,1,1,1,1,7,7
%N A269349 Kolakoski-(1,7) sequence: a(n) is length of n-th run.
%C A269349 17, 1777, 1777777711111117777777 are primes.
%H A269349 Vincenzo Librandi, <a href="/A269349/b269349.txt">Table of n, a(n) for n = 1..10000</a>
%H A269349 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.
%t A269349 seed = {1, 7}; 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
%Y A269349 Cf. similar sequences listed in A269268.
%K A269349 nonn,easy
%O A269349 1,2
%A A269349 _Vincenzo Librandi_, Feb 26 2016