28813276834domain: NAppears in sequencesNumbers n such that n-tau(n), phi(n) and n form a Heronian triangle, where tau=A000005 is the number of divisors and phi=A000010 the totient.at n=10A268281a(n) = 9a(n-1) - 9a(n-2) + a(n-3).at n=11A272365