Woodall Primes: Definition and Status
Woodall primes (sometimes called Cullen primes of the second kind) are primes of the form: Wn = n*2n-1. Chris Caldwell has a nice page about Woodall Numbers.
Wn is prime for n = 2, 3, 6, 30, 75, 81, 115, 123, 249, 362, 384, 462, 512, 751, 822, 5312, 7755, 9531, 12379, 15822, 18885, 22971, 23005, 98726, 143018, 151023, 667071 and for no other n with n < 416000. Chris Caldwell maintains the top 20 Woodall Page.
A table of ranges of exponents that have already been tested or are reserved/available for current testing for Woodall primes of the form Wn=n*2n-1.
To test for Woodall primes, you will need version 3.9 or higher of proth.exe:
- select mode, Cullen, Wn=k.2n-1
To reserve a free range of n for one of the numbers above, check the most recent reserved values of n also and then click on the link on that page to reserve your range.
Get more info here: http://www.prothsearch.net