a(n) = n^2*9^n.

Terms

a(0) =0a(1) =9a(2) =324a(3) =6561a(4) =104976a(5) =1476225a(6) =19131876a(7) =234365481a(8) =2754990144a(9) =31381059609a(10) =348678440100