Numbers k such that k and k^2 use only the digits 3, 4, 6, 7 and 9.

Terms

a(0) =3a(1) =6a(2) =7a(3) =63a(4) =9694a(5) =797963a(6) =967974a(7) =973364a(8) =9736363a(9) =99967343a(10) =796479376a(11) =973639376a(12) =7977339643a(13) =9667799474a(14) =9676449736a(15) =9676773736a(16) =9997339643a(17) =9997396643a(18) =79774334643a(19) =79979334643a(20) =96676443736a(21) =96676763736a(22) =97333344474a(23) =97464694364a(24) =797796639376a(25) =966433977764a(26) =966667677974a(27) =966676674694a(28) =967649977764