Sum of the first n even squares: a(n) = 2*n*(n+1)*(2*n+1)/3.

Terms

a(0) =0a(1) =4a(2) =20a(3) =56a(4) =120a(5) =220a(6) =364a(7) =560a(8) =816a(9) =1140a(10) =1540a(11) =2024a(12) =2600a(13) =3276a(14) =4060a(15) =4960a(16) =5984a(17) =7140a(18) =8436a(19) =9880a(20) =11480a(21) =13244a(22) =15180a(23) =17296a(24) =19600a(25) =22100a(26) =24804a(27) =27720a(28) =30856a(29) =34220