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A273473
The successive numbers of digits between two "6"s in the sequence are given by the sequence itself.
0
0, 1, 2, 3, 4, 5, 6, 60, 61, 7, 62, 8, 9, 63, 10, 16, 11, 12, 26, 13, 14, 15, 64, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 44, 45, 47, 48, 36, 49, 50, 51, 52, 53, 54, 55, 57, 58, 59, 70, 71, 72, 73, 74, 75, 77, 78, 79, 80, 81, 82, 83, 84, 85, 87, 88, 89, 90, 91, 46, 92, 93, 94, 56, 95, 97, 98, 99, 100, 101, 102, 103, 104, 105, 107, 108, 109, 110, 111, 112, 113, 114, 115, 117, 118, 119, 65, 120, 121, 76, 122, 123, 124, 67, 125, 127, 128, 129, 130, 131, 132, 133, 134, 135, 137, 138, 139, 140, 141, 142, 143, 144, 145, 147, 106, 148, 149, 150, 86, 151, 152, 153, 154, 155, 96, 157, 158, 159, 116, 170, 171, 172, 173, 68, 174, 175
OFFSET
1,3
COMMENTS
This is the lexicographically first such sequence, starting with a(1)=0, that was always extended with the smallest integer not already present in the sequence and not leading to a contradiction.
EXAMPLE
There are 0 digits between the first two "6" of the sequence [0,1,2,3,4,5,6,60]; then there is 1 digit between the next pair of "6": [60,61]; then there are 2 digits between the next pair of "6": [61,7,62]; then there are 3 digits between the next pair of "6": [62,8,9,63]; then there are 4 digits between the next pair of "6": [63,10,16]; then there are 5 digits between the next pair of "6": [16,11,12,26]; then there are 6 digits between the next pair of "6": [26,13,14,15,64]; then there are 60 digits between the next pair of "6": [64,17,18,19,20,21,22,23,24,25,27,28,29,30,31,32,33,34,35,37,38,39,40,41,42,43,44,45,47,48,36], etc. The quantities 0, 1, 2, 3, 4, 5, 6, 60,... rebuild the starting sequence.
CROSSREFS
Sequence in context: A062944 A032549 A028428 * A278941 A303164 A024643
KEYWORD
nonn,base
AUTHOR
Eric Angelini and Lars Blomberg, May 23 2016
STATUS
approved