Twice even perfect numbers. Also a(n) = M(n)*(M(n)+1), where M(n) is the n-th Mersenne prime A000668(n).
A139256
Twice even perfect numbers. Also a(n) = M(n)*(M(n)+1), where M(n) is the n-th Mersenne prime A000668(n).
Terms
- a(0) =12a(1) =56a(2) =992a(3) =16256a(4) =67100672a(5) =17179738112a(6) =274877382656
External references
- oeis: A139256