20170926, 12:31  #1 
Sep 2012
New Jersey, USA
73_{8} 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
"name field"
Jun 2011
Thailand
278D_{16} Posts 
Quote:
Congrats! A veryvery nice top finding! 

20170926, 20:41  #3 
"Nuri, the dragon :P"
Jul 2016
Good old Germany
863 Posts 
Let´s make a
What a nice finding by PG! 
20170927, 00:49  #4 
Jun 2003
634_{16} Posts 
Great news!

20170927, 16:33  #5  
Feb 2017
Nowhere
13×461 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
1010100011110_{2} Posts 

20170928, 14:55  #7 
Feb 2017
Nowhere
13·461 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
7^{2}×73 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 
Thread Tools  
Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Base 13 prime found  Siemelink  Conjectures 'R Us  0  20091005 18:27 
base 19: some k that are square can be eliminated  Siemelink  Conjectures 'R Us  2  20080506 04:01 
Prime found  paulunderwood  3*2^n1 Search  61  20080422 12:19 
Top10 twin prime found!  gd_barnes  Twin Prime Search  3  20071012 08:30 
new mersenne prime found  unregistered  Data  25  20050107 19:26 