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 A286569 #9 Apr 07 2021 12:43:29 %S A286569 1,1,1,2,1,1,2,2,2,1,3,2,1,1,4,2,2,2,1,1,1,3,5,4,3,3,2,1,1,1,6,2,1,4, %T A286569 4,3,3,2,3,3,3,3,3,5,5,7,7,8,9,9,2,5,9,1,3,7,2,3,1,1,1,1,10,2,5,6,1,7, %U A286569 4,4,3,3,1,5,5,7,3,9,9,5,5,9,9,5,9,7,5,7,11,7,9,11,11,12,12,13,14,9,5,3,15,7,9,16,4,12,11,5,1,16,3,3,17,1,6,18 %N A286569 Restricted growth sequence transform of "Hofstadter chaotic heart", A284019 (= A004001(n) - A005185(n)). %H A286569 Antti Karttunen, <a href="/A286569/b286569.txt">Table of n, a(n) for n = 1..47000</a> %e A286569 We start by setting a(1) = 1 for A284019(1) = 0. Then after, whenever A284019(k) is equal to some A284019(m) with m < k, we set a(k) = a(m). Otherwise (when the value is a new one, not encountered before), we allot for a(k) the least natural number not present among a(1) .. a(k-1). %e A286569 For n=2, as A284019(2) = 0, which was already present at A284019(1), we set a(2) = a(1) = 1. %e A286569 For n=3, as A284019(3) = 0, which was already present at n=1, we set a(3) = a(1) = 1. %e A286569 For n=4, as A284019(4) = -1, which is a new value not encountered before, we set a(4) = 1 + max(a(1),a(2),a(3)) = 2. %e A286569 For n=5, as A284019(5) = 0, which was already present at n=1, we set a(5) = a(1) = 1. %e A286569 For n=7, as A284019(7) = -1, which was already present at n=4, we set a(7) = a(4) = 2. %e A286569 For n=11, as A284019(11) = 1, which is a new value not encountered before (sign matters here), we set a(11) = 1 + max(a(1),..,a(10)) = 3. %Y A286569 Cf. A004001, A005185, A284019, A286560. %K A286569 nonn %O A286569 1,4 %A A286569 _Antti Karttunen_, May 18 2017