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Lexicographically earliest sequence of distinct terms such that the successive quantities of digits between two successive 4s are given by the succession of the sequence's digits itself.
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%I #29 Apr 20 2018 00:58:51

%S 0,1,2,3,4,40,41,5,42,6,7,43,8,9,14,10,11,44,12,13,45,46,15,16,47,17,

%T 24,18,48,19,20,34,21,22,23,54,25,26,49,27,400,28,29,30,401,31,32,33,

%U 64,74,35,36,404,414,84,37,38,402,39,424,50,434,51,94,52,53,403,55,140,56,141,57,58,142,405

%N Lexicographically earliest sequence of distinct terms such that the successive quantities of digits between two successive 4s are given by the succession of the sequence's digits itself.

%H Jean-Marc Falcoz, <a href="/A302943/b302943.txt">Table of n, a(n) for n = 1..1504</a>

%e There are:

%e 0 digits between the 4 of "4" and the 4 of "40";

%e 1 digit between the 4 of "40" and the 4 of "41";

%e 2 digits between the 4 of "41" and the 4 of "42";

%e 3 digits between the 4 of "42" and the 4 of "43";

%e 4 digits between the 4 of "43" and the 4 of "14";

%e 4 digits between the 4 of "14" and the first 4 of "44";

%e 0 digits between the 4s of "4";

%e 4 digits between the last 4 of "44" and the 4 of "45";

%e 1 digit between the 4 of "45" and the 4 of "46";

%e 5 digits between the 4 of "46" and the 4 of "47";

%e 4 digits between the 4 of "47" and the 4 of "24";

%e 2 digits between the 4 of "24" and the 4 of "47";

%e etc.

%e We see that the first column here is the succession of the digits of the sequence, as well as the size of each chunk of digits between two successive 4s.

%Y Cf. A303151 for the same idea with 1s as chunk's separators, A303157 with 2s, A303158 with 3s, A303163 with 5s, A303164 with 6s, A303166 with 7s, A303167 with 8s and A303171 with 9s.

%K nonn,base

%O 1,3

%A _Eric Angelini_ and _Jean-Marc Falcoz_, Apr 19 2018