Numbers k such that k and k^2 use only the digits 1, 3, 4, 6 and 7.

Terms

a(0) =1a(1) =4a(2) =6a(3) =131a(4) =371a(5) =376a(6) =644a(7) =646a(8) =1146a(9) =1771a(10) =3371a(11) =3431a(12) =6146a(13) =11731a(14) =33431a(15) =41731a(16) =61346a(17) =61431a(18) =64631a(19) =116776a(20) =376346a(21) =416431a(22) =641376a(23) =643146a(24) =664631a(25) =3336731a(26) =3337131a(27) =3341771a(28) =3363646a(29) =3371376