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 "2"s of the sequence: [0,1,2,20]; there is 1 digit between the next pair of "2"s: [20,21]; there are 2 digits between the next pair of "2"s: [21,3,23]; there are 20 digits between the next pair of "2"s: [23,4,5,6,7,8,9,10,11,13,14,15,16,12]; etc. The numbers 0, 1, 2, 20,... rebuild the starting sequence.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Eric Angelini and Lars Blomberg, May 23 2016
STATUS
approved