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

Terms

a(0) =0a(1) =3a(2) =30a(3) =105a(4) =252a(5) =495a(6) =858a(7) =1365a(8) =2040a(9) =2907a(10) =3990a(11) =5313a(12) =6900a(13) =8775a(14) =10962a(15) =13485a(16) =16368a(17) =19635a(18) =23310a(19) =27417a(20) =31980a(21) =37023a(22) =42570a(23) =48645a(24) =55272a(25) =62475a(26) =70278a(27) =78705a(28) =87780a(29) =97527