60933600domain: NAppears in sequencesIrrational unitary phi amicable number: numbers b such that uphi(a) = uphi(b) = 2*(a^2-b^2)^(1/2) where uphi = A047994.at n=5A046709Numbers k such that S(S(S(k))) = k, with S(n) = sigma(n)/4: 1/4-sociable numbers of order 1 or 3.at n=8A355279