a(n) = 4*(3*n+1)*(3*n+2).

Terms

a(0) =8a(1) =80a(2) =224a(3) =440a(4) =728a(5) =1088a(6) =1520a(7) =2024a(8) =2600a(9) =3248a(10) =3968a(11) =4760a(12) =5624a(13) =6560a(14) =7568a(15) =8648a(16) =9800a(17) =11024a(18) =12320a(19) =13688a(20) =15128a(21) =16640a(22) =18224a(23) =19880a(24) =21608a(25) =23408a(26) =25280a(27) =27224a(28) =29240a(29) =31328