a(n) = 1 + n^4 + n^6.

Terms

a(0) =3a(1) =81a(2) =811a(3) =4353a(4) =16251a(5) =47953a(6) =120051a(7) =266241a(8) =538003a(9) =1010001a(10) =1786203a(11) =3006721a(12) =4855371a(13) =7567953a(14) =11441251a(15) =16842753a(16) =24221091a(17) =34117201a(18) =47176203a(19) =64160001a(20) =85960603a(21) =113614161a(22) =148315731a(23) =191434753a(24) =244531251a(25) =309372753a(26) =387951931