OFFSET
1,2
COMMENTS
The sequence starts with a(1)=0. It is then extended with the smallest integer not yet present and not leading to a contradiction. The sequence is a permutation of the integers >=0.
EXAMPLE
The first two even terms that appear in the sequence are 0 and 2; between 0 and 2 there are 0 integers and this 0 corresponds to the starting 0 of the sequence.
The next even term is 4 and between 2 and 4 there are 2 integers [which are 1 and 3] and this 2 corresponds to the next term of the sequence.
The next even term is 6 and between 4 and 6 there is 1 integer [which is 5] and this 1 corresponds to the next term of the sequence.
The next even term is 8 and between 6 and 8 there are 3 integers [which are 7, 9 and 11] and this 3 corresponds to the next term of the sequence.
The next even term is 10 and between 8 and 10 there are 4 integers [which are 13, 15, 17 and 19] and this 4 corresponds to the next term of the sequence.
Etc.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Eric Angelini, Jun 01 2016
STATUS
approved