129899

Appears in sequences

• Numbers k such that sigma(phi(sigma(k))) = phi(sigma(phi(k))).at n=28A067160
• Composite solutions of the form 4k+3 of the equation (*): sigma(phi(sigma(x)))=phi(sigma(phi(x))).at n=6A112017
• a(n) = 2*F(n-1) + 2*F(n-3) + 10*F(n-5) + 9*F(n-8) where n >= 8 and F = A000045.at n=16A280932