438311domain: NAppears in sequencesComposite numbers n such that the sum of divisors of n, sigma(n), divided by the number of divisors, d(n) and sigma(n) minus n are both rational squares.at n=20A049226Numbers n such that sum of divisors, sigma(n), and sum of the proper divisors, sigma(n)-n, are both square.at n=16A176996