Numbers k such that k and k^2 use only the digits 0, 2, 6, 7 and 9.

Terms

a(0) =0a(1) =26a(2) =27a(3) =260a(4) =270a(5) =277a(6) =2600a(7) =2700a(8) =2770a(9) =26000a(10) =27000a(11) =27700a(12) =96026a(13) =96277a(14) =260000a(15) =266077a(16) =269777a(17) =270000a(18) =277000a(19) =960260a(20) =962770a(21) =996026a(22) =2600000a(23) =2660770a(24) =2696277a(25) =2697770a(26) =2700000a(27) =2770000a(28) =9602600a(29) =9627700