550095

Appears in sequences

• Numbers j such that sigma(sigma(j)) = k*j for some k.at n=44A019278
• 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 (2,6)-perfect numbers.at n=6A019283
• Odd terms of A019278: odd n such that sigma(sigma(n))/n is an integer.at n=5A205597