

A273469


The successive numbers of digits between two "4"s in the sequence are given by the sequence itself.


0



0, 1, 2, 3, 4, 40, 41, 5, 42, 6, 7, 43, 8, 9, 14, 10, 11, 12, 13, 15, 16, 17, 18, 19, 20, 21, 22, 23, 25, 26, 27, 28, 29, 30, 31, 45, 32, 33, 35, 36, 37, 38, 39, 50, 51, 52, 53, 55, 56, 57, 58, 59, 60, 61, 62, 63, 46, 65, 66, 47, 67, 68, 69, 70, 71, 72, 73, 75, 76, 77, 78, 79, 80, 81, 82, 83, 85, 86, 87, 88, 24, 89, 90, 91, 48, 92, 93, 95, 49, 96, 97, 98, 99, 100, 101, 102, 103, 105, 106, 107, 108, 109, 110, 111, 34, 112, 113, 104, 115, 116, 117, 400, 118, 119, 120, 121, 401, 122, 123, 114, 125, 126, 127, 124, 128, 129, 130, 131, 402, 132, 133, 135, 134, 136, 137, 138, 139, 150, 403, 151, 152, 153, 155, 154, 156
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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

Table of n, a(n) for n=1..145.


EXAMPLE

There are 0 digits between the first two "4" of the sequence [0,1,2,3,4,40]; then there is 1 digit between the next pair of "4": [40,41]; then there are 2 digits between the next pair of "4": [41,5,42]; then there are 3 digits between the next pair of "4": [42,6,7,43]; then there are 4 digits between the next pair of "4": [43,8,9,14]; then there are 40 digits between the next pair of "4" [14,10,11,12,13,15,16,17,18,19,20,21,22,23,25,26,27,28,29,30,31,45], etc. The quantities 0, 1, 2, 3, 4, 40,... rebuild the starting sequence.


CROSSREFS

Sequence in context: A294921 A293685 A078394 * A278939 A302943 A037326
Adjacent sequences: A273466 A273467 A273468 * A273470 A273471 A273472


KEYWORD

nonn,base


AUTHOR

Eric Angelini and Lars Blomberg, May 23 2016


STATUS

approved



