33661•2^7031232+1 is prime! The double checking effort uncovered this new prime showing once again why it is so important to conduct these re-testing efforts. Most re-tests conclusively verify the original result but if the first test had even a single memory error during the computation, there's a chance a prime could have been missed. That's what likely happened here. The discoverer, Sturle Sunde is a giant in the prime searching world. He is the #2 overall contributor to SB and also the #4 all-time contributor to GIMPS!

This result was reported at 2:03PM EST on October 17th. We've checked and re-checked the primality several times and have now submitted it to The Prime Page where it currently stands as the 10th largest known prime number ever discovered [2,116,617 digits].

Sturle, a member of team Busty Seventeen from Oslo, Norway tells us that he started crunching SB 4 years ago to "give [him] a new set of work outside of GIMPS." He currently has 160 computers crunching GIMPS and another 110 crunching SB. Only 10 of his computers were running the crucial double-check work that lead to this new discovery. He manages all his computers from the University of Oslo with intelligent scripts that only utilize them when other users aren't logged in.

We've opened a thread to comment on the discovery in the forums. Our records confirm Sturle completed over 9,000 tests before finding this result so he is quite a deserving discoverer. That said, he couldn't have done it alone and neither could we. You all keep this effort going with your dedicated crunching and your contributions are what led to this latest find. Congratulations to the entire Seventeen or Bust community!

19249 * 2^13018586 + 1 is prime!!!! SB has done it again, discovering a new largest ever non-Mersenne prime. This latest result was submitted at 00:33 EST on March 26th by Konstantin Agafonov, a member of team TSC! Russia. Konstantin is from Korolev, Russia where he works as a systems administrator for a construction company.

Before joining SB, Konstantin participated in other DC projects like Find-a-Drug, where he was the 5th largest overall contributor! Konstantin says he has used up to 100 computers on SB. This particular prime was found on one of his 3GHz Pentium 4s running Windows.

To read more about the discovery, check out the official Press Release.

Thanks to all our dedicated number crunching volunteers... some of whom have been crunching for five years now! Every one of you helped make this discovery possible! Congratulations and Happy Cinco de Mayo!

4847 * 2^3321063 + 1 is prime! This is great news as k=4847 was a relatively dense series that required more tests in a given range than the average k. The prime was discovered at 10:50PM EST on October 15th by Richard Hassler, a long-time user who has been crunching SB since August 2003.

You may notice that this prime is smaller than the last few discoveries we've made (only 999744 digits [decimal expansion]). That's because this prime was uncovered by a double check. Hopefully those of us disappointed by the artificial slowdown that double checks have caused recently are pleased that it resulted in a new discovery so quickly. We're working to correct the scoring system so that these tests are worth as much per amount of computation as larger ones. Until we do, keep in mind that although the scoring has temporarily decreased, the ease of finishing a test has gone up which does improve your chances of actually finding a prime.

Congratulations to the whole SB community! These primes are rare so take a moment to appreciate all the hard work that goes into producing them. Each SB participant helped do their part to increase the bounds of human knowledge with this discovery. Be proud of your accomplishment! 9 down -- 8 to go.

SB v2.5.0 is now available for Win32 and Linux (and FreeBSD!) on the download page.

Changes:

27653 * 2^9167433 + 1 is prime!!!! This prime weighs in at 2,759,677 digits [decimal expansion available], making it the largest non-Mersenne prime ever discovered and the 5th largest currently known prime of any form. The result was submitted at 01:25:29 EST on June 8th by Derek Gordon, a member of team LEDS. Derek is a true SB veteran. He signed up in May 2002, before we had discovered a single prime. It was back when we were only testing k=27653. So it's only fitting that after 3 years, he's the one who finally eliminated the original SB multiplier, k=27653. This will save us lots of retesting. A huge boost for the project.

Before joining SB, Derek was involved with other DC projects like Distributed.net and GIMPS. He now uses all 3 of his personal computers and 6 work computers for SB exclusively. The computer that found the prime was his Pentium 4 Windows machine at Leading Edge Design.

To read more about the discovery, check out the official Press Release.

As always, a big shout out to all our SB crunchers. None of these discoveries would be possible without the dedication of thousands of users worldwide crunching numbers. You are the heart and soul of Seventeen or Bust and this discovery is dedicated to you. Congratulations!