505555domain: NAppears in sequencesSmallest semiprime containing exactly n 5's.at n=4A104724Near-repdigit semiprimes with 5 as repeated digit.at n=39A105986Numbers k such that k and k^2 use only the digits 0, 2, 5 and 8.at n=24A136918Numbers k such that k and k^2 use only the digits 0, 2, 5, 8 and 9.at n=49A136919