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A307667 Lexicographically earliest sequence of positive terms, such that each value, say v, appears four times at indices k, k + v, k + 2*v and k + 3*v for some k.

%I A307667 #15 Apr 23 2019 02:14:55
%S A307667 1,1,1,1,2,4,2,7,2,4,2,8,6,4,7,11,9,4,6,8,12,7,14,15,6,9,11,8,7,10,6,
%T A307667 16,12,18,9,8,14,11,15,10,17,13,20,9,12,25,19,16,11,10,14,18,3,15,13,
%U A307667 3,12,17,3,10,23,3,20,16,14,19,5,13,15,18,25,5,21,24
%N A307667 Lexicographically earliest sequence of positive terms, such that each value, say v, appears four times at indices k, k + v, k + 2*v and k + 3*v for some k.
%C A307667 This sequence is a variant of A307664.
%C A307667 Graphically, we have four wavy lines.
%C A307667 Apparently every positive integer appears in the sequence.
%H A307667 Rémy Sigrist, <a href="/A307667/b307667.txt">Table of n, a(n) for n = 1..10000</a>
%H A307667 Rémy Sigrist, <a href="/A307667/a307667.png">Colored scatterplot of the first 250000 terms</a> (where the color is based on the ordinal transform of the sequence)
%H A307667 Rémy Sigrist, <a href="/A307667/a307667.gp.txt">PARI program for A307667</a>
%e A307667 For n = 1:
%e A307667 - we can set a(1) = a(2) = a(3) = a(4) = 1.
%e A307667 For n = 5:
%e A307667 - we can set a(5) = a(7) = a(9) = a(11) = 2.
%e A307667 For n = 6:
%e A307667 - a(9) is already known, hence a(6) <> 3,
%e A307667 - we can set a(6) = a(10) = a(14) = a(18) = 4.
%o A307667 (PARI) See Links section.
%Y A307667 Cf. A026242, A307664.
%K A307667 nonn
%O A307667 1,5
%A A307667 _Rémy Sigrist_, Apr 20 2019