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

Terms

a(0) =0a(1) =5a(2) =800a(3) =30375a(4) =640000a(5) =9765625a(6) =121500000a(7) =1313046875a(8) =12800000000a(9) =115330078125a(10) =976562500000