a(n) = binomial(n+8, 8)*5^n.

Terms

a(0) =1a(1) =45a(2) =1125a(3) =20625a(4) =309375a(5) =4021875a(6) =46921875a(7) =502734375a(8) =5027343750a(9) =47480468750a(10) =427324218750