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

Terms

a(0) =0a(1) =1a(2) =36a(3) =153a(4) =528a(5) =1225a(6) =2628a(7) =4753a(8) =8256a(9) =13041a(10) =20100a(11) =29161a(12) =41616a(13) =56953a(14) =77028a(15) =101025a(16) =131328a(17) =166753a(18) =210276a(19) =260281a(20) =320400a(21) =388521a(22) =468996a(23) =559153a(24) =664128a(25) =780625a(26) =914628a(27) =1062153a(28) =1230096a(29) =1413721