a(n) = (n-1) * 15^(n-2).

A027475

a(n) = (n-1) * 15^(n-2).

Terms

    a(0) =1a(1) =30a(2) =675a(3) =13500a(4) =253125a(5) =4556250a(6) =79734375a(7) =1366875000a(8) =23066015625a(9) =384433593750

External references