447678

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=24A069552
• Numbers n such that sigma(n) = 13*phi(n) (where sigma=A000203, phi=A000010).at n=14A171258
• a(n) = 6*binomial(n+1, 6).at n=16A253946
• a(n) = n*(2*n + 1)*(4*n + 1).at n=38A316224
• Numbers k such that sigma(k) = psi(k) + phi(k).at n=36A389478