Numbers k such that k and k^2 use only the digits 3, 4, 7, 8 and 9.

Terms

a(0) =3a(1) =7a(2) =88a(3) =893a(4) =938a(5) =8933a(6) =8938a(7) =98933a(8) =894393a(9) =939938a(10) =988933a(11) =989333a(12) =993878a(13) =9374833a(14) =9873438a(15) =9973933a(16) =93749333a(17) =94788438a(18) =99744393a(19) =879394393a(20) =888444933a(21) =943344833a(22) =943397978a(23) =987389933a(24) =988933438a(25) =989948933a(26) =999439788a(27) =8794793788a(28) =8797384833a(29) =9379498333