1659840domain: NAppears in sequencesSmallest k such that d(phi(k)) - phi(d(k)) = -n, where d(k) = A000005(k) and phi(k) = A000010(k).at n=30A078151Triangle read by rows. A generalization of unsigned Lah numbers, called L[3,2].at n=22A290598a(n) is the least number that has exactly n divisors with sum of digits n.at n=20A359444