168150domain: NAppears in sequencesNumbers n such that n | Sigma_2(n) + Phi(n)^2.at n=10A055696Amicable triples: numbers such that sigma(x) = sigma(y) = sigma(z) = x+y+z, x<y<z. We order these triples according to the common value of sigma. Sequence gives z numbers.at n=27A125492