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

Terms

a(0) =0a(1) =28a(2) =152a(3) =468a(4) =1072a(5) =2060a(6) =3528a(7) =5572a(8) =8288a(9) =11772a(10) =16120a(11) =21428a(12) =27792a(13) =35308a(14) =44072a(15) =54180a(16) =65728a(17) =78812a(18) =93528a(19) =109972a(20) =128240a(21) =148428a(22) =170632a(23) =194948a(24) =221472a(25) =250300a(26) =281528a(27) =315252a(28) =351568a(29) =390572