168836850domain: NAppears in sequencesNumbers such that the sum of divisors is twice the sum of the exponential divisors.at n=19A274205Numbers whose sum of coreful divisors is equal to the sum of non-coreful divisors.at n=3A308029Numbers k for which (A057723(k)-k) is equal to gcd(k-A308135(k), A057723(k)-k).at n=13A336565