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 A307664 #15 Apr 23 2019 02:15:30 %S A307664 1,1,1,2,4,2,5,2,4,6,7,5,4,9,11,6,5,7,8,10,12,6,9,14,7,11,8,3,13,10,3, %T A307664 9,12,3,8,15,11,14,17,10,18,13,19,16,12,21,22,23,25,20,15,14,26,24,13, %U A307664 17,27,28,18,16,31,19,32,29,33,15,21,35,22,20,23,34 %N A307664 Lexicographically earliest sequence of positive terms, such that each value, say v, appears three times at indices k, k + v and k + 2*v for some k. %C A307664 This sequence is a variant of A026242 where each value, say v, appears twice at indices k and k + v for some k. %C A307664 Graphically, we have three lines. %C A307664 Apparently every positive integer appears in the sequence. %H A307664 Rémy Sigrist, <a href="/A307664/b307664.txt">Table of n, a(n) for n = 1..10000</a> %H A307664 Rémy Sigrist, <a href="/A307664/a307664.gp.txt">PARI program for A307664</a> %e A307664 For n = 1: %e A307664 - we can set a(1) = a(2) = a(3) = 1. %e A307664 For n = 4: %e A307664 - we can set a(4) = a(6) = a(8) = 2. %e A307664 For n = 5: %e A307664 - a(8) is already known, hence a(5) <> 3, %e A307664 - we can set a(5) = a(9) = a(13) = 4. %o A307664 (PARI) See Links section. %Y A307664 See A307667 and A307669 for other variants. %Y A307664 Cf. A026242. %K A307664 nonn %O A307664 1,4 %A A307664 _Rémy Sigrist_, Apr 20 2019