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