a(n) = 54n^3 - 1.

Terms

a(0) =53a(1) =431a(2) =1457a(3) =3455a(4) =6749a(5) =11663a(6) =18521a(7) =27647a(8) =39365a(9) =53999a(10) =71873a(11) =93311a(12) =118637a(13) =148175a(14) =182249a(15) =221183a(16) =265301a(17) =314927a(18) =370385a(19) =431999a(20) =500093a(21) =574991a(22) =657017a(23) =746495a(24) =843749a(25) =949103a(26) =1062881a(27) =1185407a(28) =1317005a(29) =1457999