Numbers k such that k and k^2 use only the digits 3, 4, 6, 7 and 8.

Terms

a(0) =6a(1) =8a(2) =88a(3) =688a(4) =874a(5) =876a(6) =8874a(7) =8876a(8) =68474a(9) =86478a(10) =88678a(11) =683874a(12) =683876a(13) =6688374a(14) =6883876a(15) =87663474a(16) =666834678a(17) =668383478a(18) =683847844a(19) =684388374a(20) =887348678a(21) =6887436878a(22) =8646643474a(23) =8767376374a(24) =66684883478a(25) =66846374378a(26) =68466373844a(27) =87377836878a(28) =87446363374a(29) =668478484878