%I #15 Apr 23 2019 02:14:55

%S 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 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 3,12,17,3,10,23,3,20,16,14,19,5,13,15,18,25,5,21,24

%N 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 This sequence is a variant of A307664.

%C Graphically, we have four wavy lines.

%C Apparently every positive integer appears in the sequence.

%H Rémy Sigrist, <a href="/A307667/b307667.txt">Table of n, a(n) for n = 1..10000</a>

%H 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 Rémy Sigrist, <a href="/A307667/a307667.gp.txt">PARI program for A307667</a>

%e For n = 1:

%e - we can set a(1) = a(2) = a(3) = a(4) = 1.

%e For n = 5:

%e - we can set a(5) = a(7) = a(9) = a(11) = 2.

%e For n = 6:

%e - a(9) is already known, hence a(6) <> 3,

%e - we can set a(6) = a(10) = a(14) = a(18) = 4.

%o (PARI) See Links section.

%Y Cf. A026242, A307664.

%K nonn

%O 1,5

%A _Rémy Sigrist_, Apr 20 2019