Numbers k such that k and k^2 use only the digits 1, 4, 6, 7 and 8.

Terms

a(0) =1a(1) =4a(2) =8a(3) =41a(4) =88a(5) =881a(6) =4141a(7) =6441a(8) =6846a(9) =8478a(10) =8641a(11) =8874a(12) =8878a(13) =41771a(14) =68181a(15) =68474a(16) =68678a(17) =68878a(18) =86478a(19) =88776a(20) =816771a(21) =817181a(22) =846846a(23) =876178a(24) =878488a(25) =881178a(26) =6417776a(27) =6647441a(28) =7866881a(29) =8177678