a(n) = n^2*5^n.

Terms

a(0) =0a(1) =5a(2) =100a(3) =1125a(4) =10000a(5) =78125a(6) =562500a(7) =3828125a(8) =25000000a(9) =158203125a(10) =976562500a(11) =5908203125a(12) =35156250000a(13) =206298828125