login
A273478
The successive numbers of digits between two "9"s in the sequence are given by the sequence itself.
0
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 90, 91, 19, 10, 29, 11, 12, 92, 13, 14, 93, 15, 16, 39, 17, 18, 20, 49, 21, 22, 23, 24, 94, 25, 26, 27, 28, 95, 30, 31, 32, 33, 34, 35, 36, 37, 38, 40, 41, 42, 43, 44, 45, 46, 47, 48, 50, 51, 52, 53, 54, 55, 56, 57, 58, 60, 61, 62, 63, 64, 65, 66, 67, 68, 70, 71, 72, 73, 74, 75, 76, 77, 59, 78, 80, 81, 82, 83, 84, 85, 86, 87, 88, 100, 101, 102, 103, 104, 105, 106, 107, 108, 110, 111, 112, 113, 114, 115, 116, 117, 118, 120, 121, 122, 123, 124, 109, 125, 126, 127, 128, 130, 131, 69, 132, 133, 134, 79, 135, 136, 137, 138, 140, 141, 142, 143, 144, 119, 145, 146, 147, 129, 148, 150, 151, 152, 96, 153, 154, 155, 156, 157, 158, 160
OFFSET
1,3
COMMENTS
This is the lexicographically first such sequence, starting with a(1)=0; it is 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 "9" of the sequence [0,1,2,3,4,5,6,7,8,9,90]; then there is 1 digit between the next pair of "9": [90,91]; then there are 2 digits between the next pair of "9": [91,19]; then there are 3 digits between the next pair of "9": [19,10,29]; then there are 4 digits between the next pair of "9": [29,11,12,92]; then there are 5 digits between the next pair of "9": [92,13,14,93], etc. The quantities 0, 1, 2, 3, 4, 5,... rebuild the starting sequence. The next "gaps" will thus contain 6 digits, then 7, then 8, then 9, then 90...
CROSSREFS
Sequence in context: A160343 A250265 A239085 * A278944 A303171 A338831
KEYWORD
nonn,base
AUTHOR
Eric Angelini and Lars Blomberg, May 23 2016
STATUS
approved