2573571875domain: NAppears in sequencesNumbers k such that if k = Product p_i^e_i then p_i = e_i for all i.at n=12A048102Numbers whose prime factors are raised to the powers of themselves.at n=7A113853Integers that are half of their arithmetic derivatives.at n=9A165558Numbers representable as x^x * y^y, with x > y > 1.at n=16A228174