20170926, 12:31  #1 
Sep 2012
New Jersey, USA
59 Posts 
Prime found, k=168451 eliminated
On 20170917 at 21:30 PrimeGrid user Ben Maloney returned the following result:
168451*2^19375200+1 is prime! (5832522 decimal digits). That prime eliminates k=168451 from the Prime Sierpinski Problem. The prime will show up on http://www.primegrid.com/stats_psp_llr.php as soon as the Top 5000 Primes site verifies it. 
20170926, 12:46  #2  
Romulan Interpreter
Jun 2011
Thailand
261F_{16} Posts 
Quote:
Congrats! A veryvery nice top finding! 

20170926, 20:41  #3 
"Nuri, the dragon :P"
Jul 2016
Good old Germany
2^{2}·11·19 Posts 
LetÂ´s make a
What a nice finding by PG! 
20170927, 00:49  #4 
Jun 2003
2·7·113 Posts 
Great news!

20170927, 16:33  #5  
Feb 2017
Nowhere
13·373 Posts 
In the sciencealert page about the discovery that 10,223*2^31172165 + 1 is prime dated November 28, 2016 it says (my emphasis)
Quote:
Also, it looks to be the new #13 at THE LARGEST KNOWN PRIMES (Primes with 600,000 or more digits) list  which was just updated! Quote:


20170927, 16:59  #6 
Jun 2003
2×11×233 Posts 

20170928, 14:55  #7 
Feb 2017
Nowhere
12F1_{16} Posts 
Check. That was Phi(3,  143332393216) with 4055114 decimal digits.
Curiously, that page lists its rank as 15, which is correct given the new discovery that is the subject of this thread. The short list I provided the link to does not have the new discovery yet, so lists the rank as 14. 
20210806, 12:20  #8 
"99(4^34019)99 palind"
Nov 2016
(P^81993)SZ base 36
2·7^{2}·31 Posts 
Another 3 k's eliminated:
90527 (90527*2^9162167+1) 258317 (258317*2^5450519+1) 265711 (265711*2^4858008+1) Now only 7 primes > 78557 remain: 79309, 79817, 152267, 156511, 222113, 225931, 237019 
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