7597834domain: NAppears in sequencesNumber of cycles in range [A014137(n-1)..A014138(n-1)] of permutation A082345/A082346.at n=18A089406Numbers n such that sigma(n) = phi'(n), where sigma(n) is the sum of the divisors of n and phi'(n) is the arithmetic derivative of the Euler totient function of n.at n=27A261432