(n^9 + 21*n^5 - 190*n^3 + 168*n)/1260.

Terms

a(0) =0a(1) =0a(2) =0a(3) =16a(4) =216a(5) =1584a(6) =8096a(7) =32256a(8) =106992a(9) =308352a(10) =795168a(11) =1873872a(12) =4098952a(13) =8422128a(14) =16406208a(15) =30522752a(16) =54556128a(17) =94140288a(18) =157458624a(19) =256141584a(20) =406401336a(21) =630447664a(22) =958234464a(23) =1429591680a(24) =2096803280a(25) =3027697920a(26) =4309325280a(27) =6052297680a(28) =8395883496a(29) =11513946096