255367

Appears in sequences

• Numbers n such that phi(phi(n)) + sigma(sigma(n)) = phi(sigma(n)) + sigma(phi(n)), where phi=A000010 is Euler's totient function and sigma=A000203 is the sum of divisors function.at n=8A066850
• a(n) = (-1)^(n-1)*n*(4n^2-5)^2.at n=6A165935