Numbers k such that k^2 contains only digits {1,6,8}.

Terms

a(0) =1a(1) =4a(2) =9a(3) =41a(4) =109a(5) =1291a(6) =28604a(7) =78541a(8) =81619a(9) =782104a(10) =1054119a(11) =3341881a(12) =4345881a(13) =25823791a(14) =29439546a(15) =129105041a(16) =817851954a(17) =931064546a(18) =2486185454a(19) =2609955204a(20) =24862847104a(21) =786680914454