a(n) = (9*n + 8)^4.

Terms

a(0) =4096a(1) =83521a(2) =456976a(3) =1500625a(4) =3748096a(5) =7890481a(6) =14776336a(7) =25411681a(8) =40960000a(9) =62742241a(10) =92236816a(11) =131079601a(12) =181063936a(13) =244140625a(14) =322417936a(15) =418161601a(16) =533794816a(17) =671898241a(18) =835210000a(19) =1026625681