1051830

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=31A069552
• Numbers n such that sigma(n) = 13*phi(n) (where sigma=A000203, phi=A000010).at n=23A171258