Superperfect numbers: numbers k such that sigma(sigma(k)) = 2*k where sigma is the sum-of-divisors function (A000203).
A019279
Superperfect numbers: numbers k such that sigma(sigma(k)) = 2*k where sigma is the sum-of-divisors function (A000203).
Terms
- a(0) =2a(1) =4a(2) =16a(3) =64a(4) =4096a(5) =65536a(6) =262144a(7) =1073741824
External references
- oeis: A019279