Share N+/-1 Primality Proofs

[chris2be8]

From my previous attempts to prove numbers:

N+1 works for 65981^45*65981#-1 (28749 digits) but fails for 25999^8999*7386708-1 (39738 digits).

N-1 works for (2^148310*648309+1)*2-1 (44652 digits) but fails for 258570!/129285!^2+1 (77835 digits).

Chris

[MDaniello]

Originally Posted by chris2be8

From my previous attempts to prove numbers:

N+1 works for 65981^45*65981#-1 (28749 digits) but fails for 25999^8999*7386708-1 (39738 digits).

N-1 works for (2^148310*648309+1)*2-1 (44652 digits) but fails for 258570!/129285!^2+1 (77835 digits).

That's odd. Looking at the page with all primes proved by N+/-1, you can find lots of number way bigger than those thresholds. Also, i don't get why they are not around the same size (are N+1 and N-1 so different that one needs so much computation than the other?)

In the meanwhile, i found another easy one to prove: (58^1734+1)^2-2

[chris2be8]

I'm not sure what's going on. I've just rechecked the two upper limits I gave, and still got messages saying

Too big to be tested at the moment.

The limit might have been higher in the past. Do the lists say when the number was proven prime?

I've looked at a few under the More information tab and they all say:

Create time
Before November 4, 2018, 12:20 am

Which make me think they could be quite a bit older.

Chris

[MDaniello]

Originally Posted by chris2be8

I'm not sure what's going on [...]
The limit might have been higher in the past.

That, or those number were set manually as prime. Anyway, i hope someday the limits will be increased.

In the meantime i found other numbers ready to be proven. While this one was one of the usual, i found a couple to be proven simultaneously:
19992*I(25561)-1 and 12480*I(25561)+1 were both proven prime by proving I(25561) prime, which someone else did... with N-1!

[MDaniello]

I found other numbers to prove:

ID                            Number          Proven by      Digits
1100000000832798465     (12^15456-1)^2-2     N+1               33360
1100000001101920765     (234^6447-1)^2-2     N+1               30549
1100000001094394529     (1466^4249-1)^2-2    N+1               26906
1000000000011958735     8711!/8711#-1        N+1               26816
1100000001358927052     (10*I(18639)+1)/341  N-1                3894

So N+1 should work up to 33360 digits.

I also found that (244^7510+1)^2-2 is "Too big to be tested at the moment" with N+1.

This means that N+1 proving limit is below 35859 digit. My guess is 35000.

[carpetpool]

N+/-1 Proof test reports PRP:

http://www.factordb.com/index.php?id...00001361797513

(and I was expecting prime output. Not sure what's going on?)

[RichD]

Perhaps this post may be helpful.

[MDaniello]

Another easy one:
(164^4967+1)^2-2, 22003 digits!

[MDaniello]

This time a smaller one: (300^324*324^300+1)/(300^108*18^200+1) (1038 digits, proved by N-1)

[MDaniello]

This 1513-digits number was available for a N-1 proof, thanks to a certficate uploaded for a 605 digit factor!

On a similar note, a proof for (4847393^1024+1)/2 could allow a N-1 proof for (4847393^2048+1)/2 (i tried a bit of factoring, maybe a certificate would be faster?)

[MDaniello]

A few more numbers:

374^141*282^187-1        N+1   821 digits
ID 1100000001361917758   N-1   1513 digits
ID 1100000001361761140   N-1   1513 digits
ID 1100000001362222367   N-1   1513 digits
ID 1100000001362222031   N-1   1513 digits
ID 1100000001361754949   N-1   1513 digits
ID 1100000001362309552   N-1   1575 digits