Numbers k such that k and k^2 use only the digits 0, 5, 6, 7 and 9.

Terms

a(0) =0a(1) =76a(2) =760a(3) =7076a(4) =7600a(5) =70760a(6) =76000a(7) =707600a(8) =759576a(9) =760000a(10) =997976a(11) =7076000a(12) =7595760a(13) =7600000a(14) =9977976a(15) =9979760a(16) =70760000a(17) =75957600a(18) =76000000a(19) =97979976a(20) =99779760a(21) =99797600a(22) =99979976a(23) =707600000a(24) =759576000a(25) =760000000a(26) =979799760a(27) =997797600a(28) =997976000a(29) =999799760