9997000domain: NAppears in sequencesNumbers k such that k and k^2 use only the digits 0, 3, 4, 7 and 9.at n=33A136934Numbers k such that k and k^2 use only the digits 0, 4, 5, 7 and 9.at n=44A136952Numbers k such that k and k^2 use only the digits 0, 4, 7 and 9.at n=25A136960