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 A111090 #5 Nov 20 2024 12:23:00 %S A111090 1,2,11,21,112,2122,1121122,2122121122,1121122122121122, %T A111090 212212112212211211212211,112112212212112212211212212112112212 %N A111090 Successive generations of an alternating Kolakoski rule. %C A111090 Strings are obtained using the Kolakoski substitution and the additional rule: start with 1 if previous string begins with 2, start with 2 if previous string begins with 1. %C A111090 a(n+1) > a(n), and a(n) is always composed of 1s and 2s, hence a subsequence of A007931. - _Charles R Greathouse IV_, Nov 20 2024 %F A111090 As n grows a(2n-1) converges toward A025142 (red as a word) and a(2n) converges toward A025143. Conjecture : a(n) is asymptotic to c*(3/2)^n for some c. %e A111090 1-->2-->11-->21-->112-->2122 %Y A111090 Subsequence of A007931. %Y A111090 Cf. A111081, A000002. %K A111090 nonn,easy %O A111090 1,2 %A A111090 _Benoit Cloitre_, Oct 12 2005