10890040

Appears in sequences

• Numbers n such that sigma(phi(n)) = n.at n=13A018784
• Numbers k such that sigma(phi(k)) == 0 (mod k).at n=14A067144
• a(n) = A062402(2^n+1).at n=22A096856
• a(n) = 27225*n^2 + 2*n.at n=19A157820