OFFSET
1,2
COMMENTS
The last two digits of a(n) must be in ascending order (thus no term of the sequence ends in 0).
EXAMPLE
a(2) = 2 and 2 is the sum of 1 + 1 (closest digits to 2);
a(3) = 12 and 2 is the sum of 1 + 1 (closest digits to 2);
a(4) = 13 and 3 is the sum of 1 + 2 (closest digits to 3);
a(5) = 23 and 3 is the sum of 2 + 1 (closest digits to 3); etc.
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Eric Angelini, Nov 25 2020
STATUS
approved