

A273466


The successive numbers of digits between two "2"s in the sequence are given by the sequence itself.


0



0, 1, 2, 20, 21, 3, 23, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 12, 17, 18, 19, 30, 31, 33, 34, 35, 36, 37, 32, 38, 42, 39, 40, 41, 43, 44, 45, 46, 47, 48, 49, 50, 52, 51, 53, 24, 54, 55, 25, 56, 57, 62, 58, 59, 60, 72, 61, 63, 64, 65, 26, 66, 67, 68, 69, 27, 70, 71, 73, 74, 82, 75, 76, 77, 78, 79, 92, 80, 81, 83, 84, 85, 86, 120, 87, 88, 89, 90, 91, 93, 121, 94, 95, 96, 97, 98, 99, 102, 100, 101, 103, 104, 105, 123, 106, 107, 108, 112, 109, 110, 111, 113, 114, 132, 115, 116, 117, 118, 119, 130, 28
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OFFSET

1,3


COMMENTS

This is the lexicographically first such sequence, starting with a(1)=0, that has always been extended with the smallest integer not already present in the sequence and not leading to a contradiction.


LINKS



EXAMPLE

There are 0 digits between the first two "2"s of the sequence: [0,1,2,20]; there is 1 digit between the next pair of "2"s: [20,21]; there are 2 digits between the next pair of "2"s: [21,3,23]; there are 20 digits between the next pair of "2"s: [23,4,5,6,7,8,9,10,11,13,14,15,16,12]; etc. The numbers 0, 1, 2, 20,... rebuild the starting sequence.


CROSSREFS



KEYWORD

nonn,base


AUTHOR



STATUS

approved



