a(n) = 256*n^2 - 16.

Terms

a(0) =240a(1) =1008a(2) =2288a(3) =4080a(4) =6384a(5) =9200a(6) =12528a(7) =16368a(8) =20720a(9) =25584a(10) =30960a(11) =36848a(12) =43248a(13) =50160a(14) =57584a(15) =65520a(16) =73968a(17) =82928a(18) =92400a(19) =102384a(20) =112880a(21) =123888a(22) =135408a(23) =147440a(24) =159984a(25) =173040a(26) =186608a(27) =200688a(28) =215280a(29) =230384