double Mersenne number
A double Mersenne number is a number of the form . Put another way, negative one plus 2 raised to the power of a Mersenne number. The first few double Mersenne numbers (and the ones small enough to show here) are: 3, 7, 127, 170141183460469231731687303715884105727.
If a double Mersenne number is itself prime, then it is called a double Mersenne prime. Obviously its index is then a Mersenne prime. The four double Mersenne numbers listed above are all primes, but as of today, is a probable prime, despite an intense effort to find factors. (According to the Prime Pages, if it’s composite, its least prime factor must be at least .
|Title||double Mersenne number|
|Date of creation||2013-03-22 17:38:50|
|Last modified on||2013-03-22 17:38:50|
|Last modified by||PrimeFan (13766)|