K=161041 Eliminated!
On January 6th, Martin Vanc (vmv) of the Czech Republic discovered the 2,139,716 digit mega prime:
161041*2^7107964+1
This is the first ESP k elimination in nearly two years. 11 k's remain in the Extended Sierpinski problem, plus the 14 remaining k's in the Sierpinski Problem (aka "Seventeen or Bust") and the Prime Sierpinski Problem.
This is the 23rd largest known prime number. It is PrimeGrid's first mega prime of 2015, and our 68th overall.
Coincidentally, 2 additional mega primes were found shortly afterwards. Within the span of less than 15 hours three mega primes were found at PrimeGrid. The other two primes, 177*2^3411847+1 and 245*2^3411974+1, are unrelated to the Sierpinski problems. That brings our total to 70 overall.
Link to the top 5K entry: http://primes.utm.edu/primes/page.php?id=119068
Link to the official announcement: http://www.primegrid.com/download/ESP-161041.pdf
As a result of eliminating this k, we've pulled the remaining candidates with k=161041 and n>7107964 from the system. A small number of those candidates were already in the pipeline to be processed, so there may be a few that get sent out. Over 10 thousand candidates with n<10M were removed. 161041 was the third "heaviest" remaining k. Only 202705 and 238411 had more candidates.
Since we'll no longer be testing k=161041, this k has also been removed from the sieve file used for the SoB/PSP/ESP sieve. If you're running the sieve, you will get the new sieve file as soon as you get a newly generated task. Expect a large, one time download, and slightly shorter sieve times.
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My lucky number is 75898^{524288}+1 |