a(n) = (n^3 + n^2)*4^n.

Terms

a(0) =8a(1) =192a(2) =2304a(3) =20480a(4) =153600a(5) =1032192a(6) =6422528a(7) =37748736a(8) =212336640a(9) =1153433600a(10) =6090129408a(11) =31406948352a(12) =158779572224a(13) =789200240640