cp's OEIS Frontend

A263443 A self-describing sequence: when the sequence is read as a string of decimal digits, a(n) gives the starting position of an occurrence of n. This sequence is the lexicographically earliest one with this property.

%I A263443 #12 Feb 22 2020 20:54:24
%S A263443 1,2,3,4,5,6,7,8,9,10,14,1,17,130,21,50,15,28,180,33,20,37,2,200,42,
%T A263443 52,47,270,162,60,57,310,300,3,66,350,35,73,380,78,400,41,84,302,4,91,
%U A263443 460,96,480,22,104,510,110,530,115,5,55,122,580,53,132,146,136
%N A263443 A self-describing sequence: when the sequence is read as a string of decimal digits, a(n) gives the starting position of an occurrence of n. This sequence is the lexicographically earliest one with this property.
%C A263443 The sequence does not necessarily give the earliest position of a number.
%C A263443 For example, 1234 first appears at position 1, but a(1234) = 28011.
%H A263443 Paul Tek, <a href="/A263443/b263443.txt">Table of n, a(n) for n = 1..10000</a>
%H A263443 Paul Tek, <a href="/A263443/a263443.pl.txt">PERL program for this sequence</a>
%e A263443 The following table lists few first terms, with the corresponding digits induced in the overall sequence:
%e A263443 +----+------+------------------------------------------------------------+
%e A263443 | n  | a(n) | New known digits                                           |
%e A263443 +----+------+------------------------------------------------------------+
%e A263443 |  1 |    1 | 1                                                          |
%e A263443 |  2 |    2 |  2                                                         |
%e A263443 |  3 |    3 |   3                                                        |
%e A263443 |  4 |    4 |    4                                                       |
%e A263443 |  5 |    5 |     5                                                      |
%e A263443 |  6 |    6 |      6                                                     |
%e A263443 |  7 |    7 |       7                                                    |
%e A263443 |  8 |    8 |        8                                                   |
%e A263443 |  9 |    9 |         9                                                  |
%e A263443 | 10 |   10 |          10                                                |
%e A263443 | 11 |   14 |            1411                                            |
%e A263443 | 12 |    1 |                                                            |
%e A263443 | 13 |   17 |                713                                         |
%e A263443 | 14 |  130 |                   0                                 ... 14 |
%e A263443 | 15 |   21 |                    215                                     |
%e A263443 | 16 |   50 |                       0                          16        |
%e A263443 | 17 |   15 |                        15                                  |
%e A263443 | 18 |   28 |                          2818                              |
%e A263443 +----+------+------------------------------------------------------------+
%o A263443 (Perl) See Links section.
%Y A263443 Cf. A048991, A114315, A125132, A210423.
%K A263443 nonn,base
%O A263443 1,2
%A A263443 _Paul Tek_, Oct 18 2015