19999996domain: NAppears in sequencesNumbers n such that phi(n) is a proper substring of n.at n=28A066663Numbers n such that the digits of n end in phi(n).at n=29A067206a(n) = k where R(k+4) = 2.at n=6A086940Composite numbers n such that n - phi(n) is a power of 10.at n=20A248857