Numbers k such that k and k^2 use only the digits 0, 1, 5, 6 and 7.

Terms

a(0) =0a(1) =1a(2) =10a(3) =76a(4) =100a(5) =760a(6) =1000a(7) =1076a(8) =7551a(9) =7600a(10) =10000a(11) =10760a(12) =75510a(13) =76000a(14) =100000a(15) =107600a(16) =107776a(17) =707501a(18) =751666a(19) =755100a(20) =760000a(21) =1000000a(22) =1005076a(23) =1076000a(24) =1077551a(25) =1077760a(26) =1077776a(27) =7075010a(28) =7177051a(29) =7516660