a(n) = 16*n^5 - 20*n^3 + 5*n.

Terms

a(0) =0a(1) =1a(2) =362a(3) =3363a(4) =15124a(5) =47525a(6) =120126a(7) =262087a(8) =514088a(9) =930249a(10) =1580050a(11) =2550251a(12) =3946812a(13) =5896813a(14) =8550374a(15) =12082575a(16) =16695376a(17) =22619537a(18) =30116538a(19) =39480499a(20) =51040100a(21) =65160501a(22) =82245262a(23) =102738263a(24) =127125624a(25) =155937625a(26) =189750626a(27) =229188987