55328384domain: NAppears in sequencesNumbers k such that 2*k+1 is the next prime after sigma(k).at n=9A067795Numbers n such that (A000203(n)+28)/n is an integer.at n=28A162302The sum of the proper divisors of n, weighted by divisor multiplicity, equals n.at n=6A168654Numbers m with deficiency 28: sigma(m) - 2*m = -28.at n=13A392382