a(n) = (3*11^n - 1)/2.

A199018

a(n) = (3*11^n - 1)/2.

Terms

    a(0) =1a(1) =16a(2) =181a(3) =1996a(4) =21961a(5) =241576a(6) =2657341a(7) =29230756a(8) =321538321a(9) =3536921536a(10) =38906136901a(11) =427967505916

External references