Other Primes - Page 28

bur · 2022-01-11, 09:53

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?

paulunderwood · 2022-01-18, 23:36

Congrats to PrimeGrid for the "321" prime 3*2^18196595 - 1 (5,477,722 decimal digits, rank 20)

paulunderwood · 2022-01-20, 16:54

Sniped again! Congrats to Ryan Propper for the factorial prime 308084! + 1 (1,557,176 decimal digits)

bur · 2022-01-20, 17:54

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.

ryanp · 2022-01-20, 20:33

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.

ryanp · 2022-02-01, 22:23

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 \(n=500000\).

paulunderwood · 2022-02-01, 22:39

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

ryanp · 2022-02-11, 21:00

Update: search limit for \(n! ± 1\) is now at \(n=400000\).

unconnected · 2022-02-22, 07:06

New factorial prime from Mr. Propper, this will take a while to verify.

rudy235 · 2022-03-16, 15:05

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

paulunderwood · 2022-03-27, 18:25

Another 321- prime!:3 *2^18924988-1 This one with 5,696,990 and entrance rank 18. So soon after the previous one.

2022-01-11, 09:53	#298
bur Aug 2020 796581e-4;32539e-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?

2022-02-01, 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 \(n=500000\).

2022-02-22, 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

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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 796581e-4;32539e-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.

2022-02-11, 21:00	#305
ryanp Jun 2012 Boulder, CO 5·7·13 Posts	Update: search limit for \(n! ± 1\) is now at \(n=400000\).

2022-03-27, 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.