Numbers k such that k and k^2 use only the digits 0, 1, 6, 7 and 9.

Terms

a(0) =0a(1) =1a(2) =10a(3) =100a(4) =1000a(5) =7796a(6) =10000a(7) =77960a(8) =100000a(9) =107796a(10) =779600a(11) =1000000a(12) =1077776a(13) =1077960a(14) =7796000a(15) =10000000a(16) =10777760a(17) =10779600a(18) =77960000a(19) =97979996a(20) =100000000a(21) =107706969a(22) =107777600a(23) =107796000a(24) =779170199a(25) =779600000a(26) =979799960a(27) =1000000000a(28) =1007977776a(29) =1077069690