Start with a(0)=1; replace each i with 12...i, then add 1 to final digit.

A004071

Start with a(0)=1; replace each i with 12...i, then add 1 to final digit.

Terms

    a(0) =1a(1) =2a(2) =13a(3) =1124a(4) =11121235

External references