a(1) = 1; to form a(n+1), append a(n)-1, a(n)+1 at the beginning and the end of a(n), respectively. Ignore any leading 0's.

A056540

a(1) = 1; to form a(n+1), append a(n)-1, a(n)+1 at the beginning and the end of a(n), respectively. Ignore any leading 0's.

Terms

    a(0) =1a(1) =12a(2) =111213

External references