

A303166


Lexicographically earliest sequence of distinct terms such that the successive quantities of digits between two successive 7s are given by the succession of the sequence's digits itself.


9



0, 1, 2, 3, 4, 5, 6, 7, 70, 71, 8, 72, 9, 17, 10, 11, 73, 12, 13, 74, 14, 15, 27, 16, 18, 19, 37, 20, 21, 22, 47, 75, 23, 24, 25, 76, 78, 26, 28, 29, 57, 30, 31, 32, 67, 33, 79, 34, 35, 36, 38, 707, 39, 40, 41, 87, 97, 717, 170, 42, 43, 44, 700, 171, 701, 727, 45, 172, 46, 48, 49, 702, 50, 737, 51
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OFFSET

1,3


COMMENTS

The sequence starts with a(1) = 0 and is always extended with the smallest integer not yet present that doesn't lead to a contradiction. This sequence is a permutation of the numbers >= 0.


LINKS

JeanMarc Falcoz, Table of n, a(n) for n = 1..1208


EXAMPLE

There are:
0 digit between the 7 of "7" and the 7 of "70";
1 digit between the 7 of "70" and the 7 of "71";
2 digits between the 7 of "71" and the 7 of "72";
3 digits between the 7 of "72" and the 7 of "17";
4 digits between the 7 of "17" and the 7 of "73";
5 digits between the 7 of "73" and the 7 of "74";
6 digits between the 7 of "74" and the 7 of "27";
7 digits between the 7 of "27" and the 7 of "37";
7 digits between the 7 of "37" and the 7 of "47";
0 digit between the 7 of "47" and the 7 of "75";
7 digits between the 7 of "75" and the 7 of "76";
1 digit between the 7 of "76" and the 7 of "78";
etc.
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 7s.


CROSSREFS

Cf. A303151 for the same idea with 1s as chunk's separators, A303157 with 2s, A303158 with 3s, A302943 with 4s, A303163 with 5s, A303164 with 6s, A303167 with 8s and A303171 with 9s.
Sequence in context: A044909 A273475 A278942 * A024649 A037335 A028429
Adjacent sequences: A303163 A303164 A303165 * A303167 A303168 A303169


KEYWORD

nonn,base


AUTHOR

Eric Angelini and JeanMarc Falcoz, Apr 19 2018


STATUS

approved



