Prime powers p (A025475) such that the sum of the proper divisors of p is also a prime power.
A228018
Prime powers p (A025475) such that the sum of the proper divisors of p is also a prime power.
Terms
- a(0) =9a(1) =49a(2) =243a(3) =961a(4) =16129a(5) =67092481a(6) =17179607041a(7) =274876858369
External references
- oeis: A228018