Even squares: a(n) = (2*n)^2.

Terms

a(0) =0a(1) =4a(2) =16a(3) =36a(4) =64a(5) =100a(6) =144a(7) =196a(8) =256a(9) =324a(10) =400a(11) =484a(12) =576a(13) =676a(14) =784a(15) =900a(16) =1024a(17) =1156a(18) =1296a(19) =1444a(20) =1600a(21) =1764a(22) =1936a(23) =2116a(24) =2304a(25) =2500a(26) =2704a(27) =2916a(28) =3136a(29) =3364