OFFSET
1,2
COMMENTS
The sequence is started with a(1) = 1 and always extended with the smallest term not present that doesn't lead to a contradiction.
LINKS
Jean-Marc Falcoz, Table of n, a(n) for n = 1..4003
EXAMPLE
a(2) = 11 is [1] concatenated to [the first 1 of 12];
a(3) = 12 is [the last 1 of 11] concatenated to [the 2 of 21];
a(4) = 21 is [the 2 of 12] concatenated to [the 1 of 13];
a(5) = 13 is [the 1 of 21] concatenated to [the 3 of 31];
a(6) = 31 is [the 3 of 13] concatenated to [the 1 of 14];
a(7) = 14 is [the 1 of 31] concatenated to [the 4 of 41];
etc.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Jean-Marc Falcoz and Eric Angelini, Apr 24 2018
STATUS
approved