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 2022-01-11, 09:53 #298 bur     Aug 2020 79*6581e-4;3*2539e-3 10110110102 Posts New factorial prime A new factorial prime was recently reported (not yet validated): 288465! + 1 It is very close to the PRPnet search wavefront, is that a coincidence?
 2022-01-18, 23:36 #299 paulunderwood     Sep 2002 Database er0rr 466910 Posts Congrats to PrimeGrid for the "321" prime 3*2^18196595 - 1 (5,477,722 decimal digits, rank 20)
 2022-01-20, 16:54 #300 paulunderwood     Sep 2002 Database er0rr 110758 Posts Sniped again! Congrats to Ryan Propper for the factorial prime 308084! + 1 (1,557,176 decimal digits)
 2022-01-20, 17:54 #301 bur     Aug 2020 79*6581e-4;3*2539e-3 2×5×73 Posts Great to see such progress on the Factorials. Apparently there were so few over the years because few people were working on them. I still think it'd be nice if the work was organized so ranges aren't done twice or thrice, which might well be the case now.
2022-01-20, 20:33   #302
ryanp

Jun 2012
Boulder, CO

1110001112 Posts

Quote:
 Originally Posted by bur Great to see such progress on the Factorials. Apparently there were so few over the years because few people were working on them. I still think it'd be nice if the work was organized so ranges aren't done twice or thrice, which might well be the case now.
Don't know who else out there is working on these, but I've sieved (and plan to test) n! ± 1 for 300,000 <= n <= 500,000.

 2022-02-01, 22:23 #303 ryanp     Jun 2012 Boulder, CO 5×7×13 Posts Update: I've completed testing/double-checking $$n!-1$$ and $$n!+1$$ for $$150000 \le n \le 330000$$ and can confirm the only primes are the 4 known as of Jan 2022: Code: 308084! + 1 288465! + 1 208003! - 1 150209! + 1 Continuing on up to $$n=500000$$.
2022-02-01, 22:39   #304
paulunderwood

Sep 2002
Database er0rr

7·23·29 Posts

Quote:
 Originally Posted by ryanp Update: I've completed testing/double-checking $$n!-1$$ and $$n!+1$$ for $$150000 \le n \le 330000$$ and can confirm the only primes are the 4 known as of Jan 2022: Code: 308084! + 1 288465! + 1 208003! - 1 150209! + 1 Continuing on up to $$n=500000$$.
I suppose that PrimeGrid's factorial sub-project is defunct now, unless they start at n=500000

 2022-02-11, 21:00 #305 ryanp     Jun 2012 Boulder, CO 5·7·13 Posts Update: search limit for $$n! ± 1$$ is now at $$n=400000$$.
 2022-02-22, 07:06 #306 unconnected     May 2009 Moscow, Russia 295410 Posts New factorial prime from Mr. Propper, this will take a while to verify. Last fiddled with by unconnected on 2022-02-22 at 07:06
2022-03-16, 15:05   #307
rudy235

Jun 2015
Vallejo, CA/.

33·43 Posts
Will there ever be an Official Announcement?

Quote:
 Originally Posted by paulunderwood Congrats to PrimeGrid for the "321" prime 3*2^18196595 - 1 (5,477,722 decimal digits, rank 20)
.
Quote:
 6 3*2^18196595-1 5,477,722 (decimal) vaclav_m (primes) BOINC@Poland 2022-01-08 20:46:05 UTC T5K No official Announcement 321 Prime Search 217,652.558

 2022-03-27, 18:25 #308 paulunderwood     Sep 2002 Database er0rr 7·23·29 Posts Another 321- prime!:3 *2^18924988-1 This one with 5,696,990 and entrance rank 18. So soon after the previous one.

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