mersenneforum.org

mersenneforum.org (https://www.mersenneforum.org/index.php)
-   Miscellaneous Math (https://www.mersenneforum.org/forumdisplay.php?f=56)
-   -   Thread for posting tiny primes (https://www.mersenneforum.org/showthread.php?t=13650)

3.14159 2010-09-05 21:27

[QUOTE=Charles]I have now proved the primality of 618970019642690137449562111, a p27, with trial division. This was the hardest proof by trial division I had ever attempted.
[/QUOTE]

Please, tell me, exactly how did your computer's speed increase [B]exponentially[/B]?

If it took me about 10-15 minutes to prove a p22 prime; It should have taken you a similar timeframe to prove the same number prime; A number ≈70000-75000 times that size should have taken many thousands of times longer.

Or did you get started 3-6 months ago?

kar_bon 2010-09-05 21:29

[QUOTE=3.14159;228575]Please, tell me, exactly how did your computer's speed increase [B]exponentially[/B]?[/QUOTE]

You should look closer here. That's what I meant!

618970019642690137449562111 = 2^89-1 and therfore only factors = 2kp+1 have to be considered and tested!

3.14159 2010-09-05 21:32

[QUOTE=Karsten]618970019642690137449562111 = 2^89-1 and therfore only factors = 2kp+1 have to be considered and tested!
[/QUOTE]

Mersenne number? Cheating not allowed, :smile:

[B]General numbers only. [/B] Optionally, Proth numbers. Take a probable prime and prove it prime, using trial-factoring only.

So, Charles, try again, with a general or Proth number. (Can either be b = 2 or regular). Unless your computer speeds up by 10000 on demand, let's see how that works out.

CRGreathouse 2010-09-05 21:34

[QUOTE=3.14159;228577]Mersenne number? Cheating not allowed[/QUOTE]

Really... did you think I'd enter into one of these without some sort of trick?

3.14159 2010-09-05 21:48

[QUOTE=Charles]Really... did you think I'd enter into one of these without some sort of trick?
[/QUOTE]

The first was composite, divisible by 7, and the next is a Mersenne number.

You so far have contributed nothing. Next!

3.14159 2010-09-05 21:52

Reporting for 17 or 18: (981248619155265231198804096876768467232996282812538785080944608471724730019235498676*3000!+1)/486830979235504387397288386896757349991446828735164830762828213017832532827952201 is prime, 9051 digits.

This may probably be in Special Cofactor.

science_man_88 2010-09-05 21:55

[QUOTE=3.14159;228581]The first was composite, divisible by 7, and the next is a Mersenne number.

You so far have contributed nothing. Next![/QUOTE]

the one thing i see you contributing to most is a headache by changing rules so much.

3.14159 2010-09-05 22:27

[QUOTE=science_man_88]the one thing i see you contributing to most is a headache by changing rules so much.
[/QUOTE]

I'm merely keeping trickeries out of the list.

CRGreathouse 2010-09-05 22:29

[QUOTE=3.14159;228581]The first was composite, divisible by 7[/QUOTE]

Copy/paste error. I fixed it before you posted, but you quoted the unedited version.

CRGreathouse 2010-09-05 22:30

[QUOTE=science_man_88;228583]the one thing i see you contributing to most is a headache by changing rules so much.[/QUOTE]

+1. If I had a nickel for every time he did that... well, I'd have about a buck. But still, that's a lot of rules changes.

kar_bon 2010-09-05 22:43

[QUOTE=CRGreathouse;228589]+1. If I had a nickel for every time he did that... well, I'd have about a buck. But still, that's a lot of rules changes.[/QUOTE]

And it's a ridiculous point of his list:

1. Wasting CPU-cycles to find the biggest prime proven by trial division.
2. He can't recognize simple 'easy' numbers.
3. He can't prove if such number is proven only by trial division.


All times are UTC. The time now is 22:43.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.