## Woodall Primes: Definition and Status

### News Flash!

**On December 21, 2007, Matthew Thompson, participating in the PrimeGrid project, found the largest known Woodall prime, the first mega-digit Woodall, 3752948*2^3752948-1**

### News Flash!

**On August 13, 2007, Stephen Kohlman, participating in the PrimeGrid project, found the largest known Woodall prime, 2367906*2^2367906-1**

### News Flash!

**On August 4, 2007, Lasse Mejling Andersen, participating in the PrimeGrid project, found the largest known Woodall prime, 2013992*2^2013992-1**

Woodall Primes are
Woodall numbers that are prime and of the form
*W*_{n} = *n* · 2^{n} − 1.

*W*_{n} 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, 1195203, 1268979, 1467763,
2013992, 2367906, 3752948 and for no other *n *__<__ 11,000,000.
Chris Caldwell maintains the
top 20 Woodall Page.

A list of contributors to the Woodall project is here.

PrimeGrid is coordinating a
distributed search for Woodall primes using BOINC.

To search for Woodall Primes of other bases, check out Steven Harvey's
Generalized Woodall Search

Cullen numbers (*C*_{n} = *n* · 2^{n} + 1)
are related to Woodall numbers. Check
here for the Cullen prime search.

Back to index Page

If you have any questions about the Woodall Search, you can e-mail Mark Rodenkirch or
Ray Ballinger

URL: http://www.prothsearch.net/woodall.html

Last Modified: March 19, 2013