3365438domain: NAppears in sequencesNumbers n such that |phi(n+1)-phi(n)| = |d(n+1)-d(n)|, where phi is Euler's totient function and d(n) = number of divisors of n.at n=20A066219Numbers n such that phi(n) + d(n) = phi(n+1) + d(n+1), where phi(n) is the Euler totient function of n and d(n) the number of divisors of n.at n=14A259496