The 'No Prime Left Behind' Project (NPLB)

Project Information:

This project searches for Riesel primes of the form k · 2 n - 1 with odd k and
300 < k < 1001 and n > 260.000 not reserved by others with highly presieved ranges.

This project was founded with the intention of managing and continuing the PrimeSearch-Project (to be found here)
in a more interesting manner for everyone. There are efforts for both lone searchers and for coordinated team efforts,
which results in a higher precision of prime reporting.

For more information visit the forum Software/Instructions/Questions.

Some scoring statistics are also available with found primes and completed ranges by contributors (have to be updated)!

Background Information:

PrimeSearch was set up by Michael Hartley in 2001 for the search of prime numbers of the form k·2n-1
with 255 < k < 1001 and 16000 < n < 600000. The range for k < 255 was added in 2007.

Some reasons for creating a project like NPLB:
Gary Barnes decided to change all these deficiencies and begun to sieve 400 < k < 1001 from n = 260000 to 600000 in 2007.
Independently also in 2007 Karsten Bonath begun to sieve and test a range of 100 k's with k > 300.
So just a matter of time NPLB was born.

On Jan 21, 2008 this project started with a forum here.

Detailed Search Information:

Team Drives:

At first there are three different ranges for 400 < k < 1001 for searching with the following conditions: The whole range from n = 260000 to 600000 was presieved up to p = 5·1012 (= 5 Trillions = 5 T).


See the Races-Overview!

Future Information:

300 < k < 400:

This range will be added when the sieving is done. Some of those k's will be left for individual searching.
Additional searches may begin above n = 600000 for k's previously searched to that limit.

Double-checking of 300 < k < 1001 for n = 100000 to 260000:

Double-checking has already been completed for this k-range for n < 100000 in 2007 by Gary Barnes.
Many missing primes and errors were found there.

Double-checking of n = 260000 to 600000 for already completed k-values:

This is being run in conjunction with the main team drive.

Goals for this project:

And now...

Thanks and come join us for the fun at No Prime Left Behind!