Squares composed of digits {1,6,9}.

Terms

a(0) =1a(1) =9a(2) =16a(3) =169a(4) =196a(5) =961a(6) =69169a(7) =69696a(8) =9696996a(9) =16966161a(10) =611919169a(11) =6661661161a(12) =696199996996