a(n) = (4*n)^2.

Terms

a(0) =0a(1) =16a(2) =64a(3) =144a(4) =256a(5) =400a(6) =576a(7) =784a(8) =1024a(9) =1296a(10) =1600a(11) =1936a(12) =2304a(13) =2704a(14) =3136a(15) =3600a(16) =4096a(17) =4624a(18) =5184a(19) =5776a(20) =6400a(21) =7056a(22) =7744a(23) =8464a(24) =9216a(25) =10000a(26) =10816a(27) =11664a(28) =12544a(29) =13456