a(n) = n^3 * 5^n.

Terms

a(0) =0a(1) =5a(2) =200a(3) =3375a(4) =40000a(5) =390625a(6) =3375000a(7) =26796875a(8) =200000000a(9) =1423828125a(10) =9765625000a(11) =64990234375a(12) =421875000000