3932040

Appears in sequences

• Let sigma_m (n) be result of applying sum-of-divisors function m times to n; call n (m,k)-perfect if sigma_m (n) = k*n; sequence gives the (2,13)-perfect numbers.at n=2A019290
• Numbers n such that denominator(sigma(sigma(n))/n) = denominator(sigma(sigma(s))/s) where s = sigma(n).at n=32A275321
• Subsequence of terms of A019278 whose sum of divisors is also a term of A019278.at n=20A292949