Numbers k such that k and k^2 use only the digits 4, 5, 6, 7 and 8.

Terms

a(0) =8a(1) =74a(2) =76a(3) =88a(4) =684a(5) =758a(6) =766a(7) =888a(8) =6684a(9) =6766a(10) =6888a(11) =7588a(12) =7666a(13) =8874a(14) =66684a(15) =67666a(16) =68474a(17) =68888a(18) =74476a(19) =74758a(20) =76476a(21) =76478a(22) =76666a(23) =86478a(24) =86878a(25) =666684a(26) =667666a(27) =668474a(28) =675684a(29) =675758