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

Terms

a(0) =0a(1) =0a(2) =20a(3) =180a(4) =816a(5) =2600a(6) =6660a(7) =14700a(8) =29120a(9) =53136a(10) =90900a(11) =147620a(12) =229680a(13) =344760a(14) =501956a(15) =711900a(16) =986880a(17) =1340960a(18) =1790100a(19) =2352276a(20) =3047600a(21) =3898440a(22) =4929540a(23) =6168140a(24) =7644096a(25) =9390000a(26) =11441300