20180616, 08:04  #1 
Sep 2013
Perth, Au.
2·7^{2} Posts 
S/R Base 5 Primes reported in 2017+
Congratulations to Frank Schwegler for finding the 1st SR5 prime of 2017.
The prime 171362*5^24009961 found on 25 August 2017 eliminates k=171362 from the base 5 Riesel problem. The prime is 1,678,230 digits long and entered Chris Caldwell's “The Largest Known Primes Database” (http://primes.utm.edu/primes) ranked 57th overall. 73 k's then remained in the Riesel Base 5 Problem. Congratulations to Håkan Lind for finding the 2nd SR5 prime of 2017. The prime 301562*5^24086461 found on 17 September 2017 eliminates k=301562 from the base 5 Riesel problem. The prime is 1,683,577 digits long and entered Chris Caldwell's “The Largest Known Primes Database” (http://primes.utm.edu/primes) ranked 57th overall. 72 k's now remain in the Riesel Base 5 Problem. The base 5 Sierpinski problem has 33 k's remaining. Primegrid is currently running a 5 day challenge on the Sierpinski / Riesel Base 5 (SR5) project, ends 19th June 2018 00:00 UTC. For details, please read the post in the PrimeGrid forum: http://www.primegrid.com/forum_thread.php?id=8027 
20180619, 19:44  #2 
Dec 2011
After milion nines:)
1,597 Posts 
And new prime in this class is fall!

20180622, 13:03  #3 
Dec 2011
After milion nines:)
1,597 Posts 
And another one :)
After long time two primes in difference of few days. 
20180624, 05:22  #4 
Sep 2013
Perth, Au.
2×7^{2} Posts 
S/R Base 5 Primes reported in 2018
Congratulations to Selya Tsuji for finding the 1st SR5 prime of 2018.
The prime 327926*5^25428381 found on 19 June 2018 eliminates k=327926 from the base 5 Riesel problem. The prime is 1,777,374 digits long and entered Chris Caldwell's “The Largest Known Primes Database” (http://primes.utm.edu/primes) ranked 60th overall. 71 k's now remain in the Riesel Base 5 Problem. Congratulations to Jiří Bočan for finding the 2nd SR5 prime of 2018. The prime 81556*5^2539960+1 found on 20 June 2018 eliminates k=81556 from the base 5 Sierpinski problem. The prime is 1,775,361 digits long and entered Chris Caldwell's “The Largest Known Primes Database” (http://primes.utm.edu/primes) ranked 61st overall. 32 k's now remain in the Sierpinski Base 5 Problem. Both of these primes were found just after the Primegrid SR5 challenge. 
20180625, 11:27  #5 
Mar 2018
10000001_{2} Posts 
To be pedantic, both workunits were sent out during the challenge :)

20180805, 01:18  #6 
Sep 2013
Perth, Au.
2·7^{2} Posts 
S/R Base 5 Primes reported in 2018
Congratulations to Honza Cholt for finding the 3rd SR5 prime of 2018.
The prime 66916*5^26286091 found on 29 July 2018 eliminates k=66916 from the base 5 Riesel problem. The prime is 1,837,324 digits long and entered Chris Caldwell's “The Largest Known Primes Database” (http://primes.utm.edu/primes) ranked 59th overall. 70 k's now remain in the Riesel Base 5 Problem. 
20180916, 01:10  #7 
Sep 2013
Perth, Au.
2·7^{2} Posts 
S/R Base 5 Prime reported in 2018
Congratulations again to Honza Cholt for finding the 4th SR5 prime of 2018.
The prime 194368*5^26380451 found on 15 August 2018 eliminates k=194368 from the base 5 Riesel problem. The prime is 1,843,920 digits long and entered Chris Caldwell's “The Largest Known Primes Database” (http://primes.utm.edu/primes) ranked 60th overall. 69 k's now remain in the Riesel Base 5 Problem. 
20190427, 07:33  #8 
Dec 2011
After milion nines:)
11000111101_{2} Posts 
And we have new SR5 prime!
138514*5^2771922+1 found by Ken Ito on 26 April 2019 1937496 digits, position 63 
20190427, 10:23  #9  
May 2009
Moscow, Russia
3^{2}×317 Posts 
Quote:


20190427, 18:04  #10 
Dec 2011
After milion nines:)
1,597 Posts 

20190621, 18:12  #11 
Dec 2011
After milion nines:)
1,597 Posts 

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