Numbers k such that k^2 contains only digits {1,6,9}.

Terms

a(0) =1a(1) =3a(2) =4a(3) =13a(4) =14a(5) =31a(6) =263a(7) =264a(8) =3114a(9) =4119a(10) =24737a(11) =81619a(12) =834386a(13) =1382737a(14) =9959514a(15) =10775719a(16) =341608987a(17) =836460469a(18) =998053937a(19) =24737858031a(20) =40201507014a(21) =99599046013