428178002569domain: NAppears in sequencesSquarefree numbers (A005117) of the form p*q*r with prime factors p, q, r with q = 2*p-1 and r = 2*q-1.at n=20A231815Super pseudoprimes to both bases 2 and 3 (A333130) with more than two prime factors (counted with multiplicity).at n=7A333131