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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.
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%I #12 Feb 22 2020 20:54:24

%S 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 52,47,270,162,60,57,310,300,3,66,350,35,73,380,78,400,41,84,302,4,91,

%U 460,96,480,22,104,510,110,530,115,5,55,122,580,53,132,146,136

%N 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 The sequence does not necessarily give the earliest position of a number.

%C For example, 1234 first appears at position 1, but a(1234) = 28011.

%H Paul Tek, <a href="/A263443/b263443.txt">Table of n, a(n) for n = 1..10000</a>

%H Paul Tek, <a href="/A263443/a263443.pl.txt">PERL program for this sequence</a>

%e The following table lists few first terms, with the corresponding digits induced in the overall sequence:

%e +----+------+------------------------------------------------------------+

%e | n | a(n) | New known digits |

%e +----+------+------------------------------------------------------------+

%e | 1 | 1 | 1 |

%e | 2 | 2 | 2 |

%e | 3 | 3 | 3 |

%e | 4 | 4 | 4 |

%e | 5 | 5 | 5 |

%e | 6 | 6 | 6 |

%e | 7 | 7 | 7 |

%e | 8 | 8 | 8 |

%e | 9 | 9 | 9 |

%e | 10 | 10 | 10 |

%e | 11 | 14 | 1411 |

%e | 12 | 1 | |

%e | 13 | 17 | 713 |

%e | 14 | 130 | 0 ... 14 |

%e | 15 | 21 | 215 |

%e | 16 | 50 | 0 16 |

%e | 17 | 15 | 15 |

%e | 18 | 28 | 2818 |

%e +----+------+------------------------------------------------------------+

%o (Perl) See Links section.

%Y Cf. A048991, A114315, A125132, A210423.

%K nonn,base

%O 1,2

%A _Paul Tek_, Oct 18 2015