Prime found, k=168451 eliminated
On 20170917 at 21:30 PrimeGrid user Ben Maloney returned the following result:
[url=http://primes.utm.edu/primes/page.php?id=123905][b]168451*2^19375200+1 is prime! (5832522 decimal digits)[/b][/url]. That prime eliminates k=168451 from the Prime Sierpinski Problem. The prime will show up on [url]http://www.primegrid.com/stats_psp_llr.php[/url] as soon as the Top 5000 Primes site verifies it. 
[QUOTE=JimB;468589]On 20170917 at 21:30 PrimeGrid user Ben Maloney returned the following result:
[URL="http://primes.utm.edu/primes/page.php?id=123905"][B]168451*2^19375200+1 is prime! (5832522 decimal digits)[/B][/URL]. That prime eliminates k=168451 from the Prime Sierpinski Problem. The prime will show up on [URL]http://www.primegrid.com/stats_psp_llr.php[/URL] as soon as the Top 5000 Primes site verifies it.[/QUOTE] Yarrrrr! :chappy: Congrats! A veryvery nice top finding! 
LetÂ´s make a :party:
What a nice finding by PG! 
Great news!:bow wave::groupwave::bounce wave::party:

In the [url=https://www.sciencealert.com/thisnewprimenumbercouldhelpsolveadecadesoldpuzzle]sciencealert page about the discovery that 10,223*2^31172165 + 1 is prime[/url] dated November 28, 2016 it says (my emphasis)[quote]In fact, among the 10 largest known prime numbers, our new prime is the only prime that is not a Mersenne number, [b]and the only known nonMersenne prime over 4 million digits[/b].[/quote]
Though this new discovery isn't large enough to displace any of the "top ten known primes," that last phrase has gone out of date. Also, it looks to be the new #13 at [url=https://primes.utm.edu/primes/lists/short.txt]THE LARGEST KNOWN PRIMES (Primes with 600,000 or more digits)[/url] list  which was just updated! [quote]The letters after the rank refer to when the prime was submitted. 'a' is this month, 'b' last month...       rank description ___________ digits __ who __ year comment       12a 919444^1048576+1 ____ 6253210 L4286 2017 Generalized Fermat 13 Phi(3,123447^524288) __ 5338805 L4561 2017 Generalized unique[/quote] Congratulations! :party: 
[QUOTE=Dr Sardonicus;468653]Though this new discovery isn't large enough to displace any of the "top ten known primes," that last phrase has gone out of date.
[/QUOTE] That went out of date in Jan 2017 
[QUOTE=axn;468657]That went out of date in Jan 2017[/QUOTE]
Check. That was [url=https://primes.utm.edu/primes/page.php?id=122812]Phi(3,  143332393216)[/url] 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. 
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 
All times are UTC. The time now is 16:05. 
Powered by vBulletin® Version 3.8.11
Copyright ©2000  2021, Jelsoft Enterprises Ltd.