OFFSET
1,2
COMMENTS
If a(n-1) ends in 1, a(n) must begin with 2 (i.e., a forced increase by 1).
There are no numbers in the sequence with first digit 9.
EXAMPLE
11 is followed by 21 in the sequence since it can't be followed by a number starting with 0.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Enrique Navarrete, Jun 19 2017
STATUS
approved