a(n) = 8*n^3*((2*n-1)^2 - 4*n + 4).

Terms

a(0) =0a(1) =8a(2) =320a(3) =3672a(4) =18944a(5) =65000a(6) =174528a(7) =397880a(8) =806912a(9) =1498824a(10) =2600000a(11) =4269848a(12) =6704640a(13) =10141352a(14) =14861504a(15) =21195000a(16) =29523968a(17) =40286600a(18) =53980992a(19) =71168984a(20) =92480000a(21) =118614888a(22) =150349760a(23) =188539832a(24) =234123264a(25) =288125000a(26) =351660608a(27) =425940120