2835756domain: NAppears in sequencesNumbers n such that sigma(phi(n)) = n.at n=10A018784Numbers k such that sigma(phi(k)) == 0 (mod k).at n=11A067144Triangle: Newton expansion of C(n,m)^3, read by rows.at n=60A262704Diagonal of the rational function 1/(1 - (wxz + wy + wz + xy + xz + y + z)).at n=5A274786