Congratulations to Frank Schwegler for finding the 1st SR5 prime of 2017.

The prime 171362*5^2400996-1 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*5^2408646-1 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