Odd terms of A019278: odd n such that sigma(sigma(n))/n is an integer.
A205597
Odd terms of A019278: odd n such that sigma(sigma(n))/n is an integer.
Terms
- a(0) =1a(1) =15a(2) =21a(3) =1023a(4) =29127a(5) =550095a(6) =355744082763
External references
- oeis: A205597