7607600domain: NAppears in sequencesa(n) = least common multiple of {1, 4, 7, 10, 13 ..., 3n+1} (A016777).at n=8A051536a(n) = least common multiple of {1, 4, 7, 10, 13 ..., 3n+1} (A016777).at n=9A051536Numbers k such that k and k^2 use only the digits 0, 5, 6, 7 and 8.at n=20A136963