a(n) = (10*n + 2)^2.

Terms

a(0) =4a(1) =144a(2) =484a(3) =1024a(4) =1764a(5) =2704a(6) =3844a(7) =5184a(8) =6724a(9) =8464a(10) =10404a(11) =12544a(12) =14884a(13) =17424a(14) =20164a(15) =23104a(16) =26244a(17) =29584a(18) =33124a(19) =36864a(20) =40804a(21) =44944a(22) =49284a(23) =53824a(24) =58564a(25) =63504a(26) =68644a(27) =73984a(28) =79524a(29) =85264