a(n) = 3*(n-2)*(n-3)*(3*n^2-3*n-8)/2.

Terms

a(0) =0a(1) =0a(2) =84a(3) =468a(4) =1476a(5) =3540a(6) =7200a(7) =13104a(8) =22008a(9) =34776a(10) =52380a(11) =75900a(12) =106524a(13) =145548a(14) =194376a(15) =254520a(16) =327600a(17) =415344a(18) =519588a(19) =642276a(20) =785460a(21) =951300a(22) =1142064a(23) =1360128a(24) =1607976a(25) =1888200a(26) =2203500a(27) =2556684a(28) =2950668a(29) =3388476