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
KEYWORD
nonn,base
AUTHOR
Eric Angelini and Lars Blomberg, May 23 2016
STATUS
approved