Squares composed of digits {3,6,9}.

Terms

a(0) =9a(1) =36a(2) =3969a(3) =69696a(4) =93636a(5) =3663396a(6) =9696996a(7) =966339396a(8) =6693366969a(9) =36333696996a(10) =63396693369a(11) =96693633936