200260

Appears in sequences

• Numbers k such that phi(k) = sigma(core(k)) where phi(k) is the Euler totient function, sigma(k) the sum of divisors of k and core(k) the squarefree part of k (the smallest integer such that k*core(k) is a square).at n=17A069552
• Numbers n such that sigma(n) = 7*phi(n).at n=17A136540
• Numbers k such that (19*10^k + 101) / 3 is prime.at n=30A276672
• Numbers k such that sigma(k) = psi(k) + phi(k).at n=26A389478