781347841domain: NAppears in sequencesComposite numbers k such that phi(k) divides d*(k - 1) for some squarefree divisor d of k - 1.at n=23A337316Carmichael numbers k for which bigomega(phi(k)) < bigomega(k-1), where bigomega gives the number of prime divisors, counted with multiplicity.at n=9A339909