a(n) = (4*n+8)*n^2.

Terms

a(0) =0a(1) =12a(2) =64a(3) =180a(4) =384a(5) =700a(6) =1152a(7) =1764a(8) =2560a(9) =3564a(10) =4800a(11) =6292a(12) =8064a(13) =10140a(14) =12544a(15) =15300a(16) =18432a(17) =21964a(18) =25920a(19) =30324a(20) =35200a(21) =40572a(22) =46464a(23) =52900a(24) =59904a(25) =67500a(26) =75712a(27) =84564a(28) =94080a(29) =104284