OFFSET
1,2
COMMENTS
The sequence starts with a(1) = 1 and was always extended with the smallest integer not yet present that does not lead to a contradiction.
LINKS
Jean-Marc Falcoz, Table of n, a(n) for n = 1..10001
EXAMPLE
The sequence begins with 1, 9, 11, 91, 92, 8, 2, 81, 93, 71... The two digits that border the first comma are 1 and 9 that sum up to 10 as required; the 2nd comma is bordered by 9 and 1; the 3rd one by 1 and 9 again; the 4th one by 1 and 9 too; the 5th one by 2 and 8; the 6th one by 8 and 2; the 7th one by 2 and 8 again; the 8th one by 1 and 9; the 9th one by 3 and 7, etc.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Eric Angelini and Jean-Marc Falcoz, Nov 08 2016
STATUS
approved