680609

Appears in sequences

• Composite numbers n such that sigma(n)+12 = sigma(n+12).at n=19A054902
• Composite numbers k such that both phi(k+12) = phi(k) + 12 and sigma(k+12) = sigma(k) + 12.at n=4A056777
• Composite numbers n such that n'=(n+12)', where n' is the arithmetic derivative of n.at n=6A257107