a(n) = 18*a(n-1) - a(n-2).

A023039

a(n) = 18*a(n-1) - a(n-2).

Terms

    a(0) =1a(1) =9a(2) =161a(3) =2889a(4) =51841a(5) =930249a(6) =16692641a(7) =299537289a(8) =5374978561a(9) =96450076809

External references