Factoring database

[henryzz]

Originally Posted by mdettweiler

Quick question: how exactly does the "add sequence to workers" button work? I tried it earlier today on a relatively small sequence (~20 digits, if memory serves), and it ran for a few seconds, but then disappeared from the worker queue with absolutely no additions to the sequence. Am I misunderstanding something about this?

i think it is something like tf to 1e6 and ecm to low limits
if neither of them find a factor it stops

[Mini-Geek]

I'm pretty sure it's supposed to run it until it hits a c70 or greater that would need SIQS.

[axn]

Originally Posted by mdettweiler

Quick question: how exactly does the "add sequence to workers" button work? I tried it earlier today on a relatively small sequence (~20 digits, if memory serves), and it ran for a few seconds, but then disappeared from the worker queue with absolutely no additions to the sequence. Am I misunderstanding something about this?

Originally Posted by henryzz

i think it is something like tf to 1e6 and ecm to low limits
if neither of them find a factor it stops

No. It uses msieve also. It stops when it hits a "hard" composite > 70 digits. However, there is a known issue with msieve: it sometimes fails to split factors of ~20 digits. In such cases the process stops. If you can manually split the factor (eg:- using Alpertron's applet) and submit it to the db, then clicking on "Add Seq to Worker" will take you further.

[Andi47]

@Syd: Do you (frequently) read this thread in the aliquot sequences forum? There are a few new bugs (e.g. squared line bugs) in some sequences reported there.

[Mini-Geek]

http://factordb.com/search.php?aq=350476 has the squared line bug. Something I did that probably caused it: (oops!) I clicked my shortcut to send the status to the DB twice, and it re-sent it as it was sending the first time.

[Andi_HB]

Last Night the Database Workers have found a nice p44 for this c186 Number (58*10^205+23)/9
The p44 was found with ecm B1 3e6

Let the factors coming

[WraithX]

Hello Syd,

I have a couple of questions about the database:
1) How do you prove a number is prp? I see you use Miller-Rabin tests, but to which bases? Are they fixed bases, or random bases? And how many bases?

2) How do you prove a number is prime? Do you use Primo, or something built into pari/gp, or something else?

3) I've noticed that some of the Mersenne primes are not showing up as primes in your data base, they are only showing up as prp. Can this be updated? (The Mersenne primes up to M1279 are prime, after that they are prp)

[jasonp]

If he uses msieve for probable primality tests:
- numbers less than 10^10 are proven prime by trial division
- larger numbers have 20 iterations of Miller-Rabin with random bases

[10metreh]

When I enter a new factor for sequence 130396 in the "Know a factor?" box, this error appears:

Fatal error: Cannot redeclare sequence() (previously declared in /var/www/sequence.php:18) in /var/www/sequence.php on line 123

Oddly enough, when I refresh the page, it is back to normal, and the new factor is included.

[Mini-Geek]

Originally Posted by 10metreh

When I enter a new factor for sequence 130396 in the "Know a factor?" box, this error appears:

Fatal error: Cannot redeclare sequence() (previously declared in /var/www/sequence.php:18) in /var/www/sequence.php on line 123

Oddly enough, when I refresh the page, it is back to normal, and the new factor is included.

I've noticed that on every sequence. Not sure why I didn't report it before.

[WraithX]

Originally Posted by WraithX

Hello Syd,

I have a couple of questions about the database:
1) How do you prove a number is prp? I see you use Miller-Rabin tests, but to which bases? Are they fixed bases, or random bases? And how many bases?

2) How do you prove a number is prime? Do you use Primo, or something built into pari/gp, or something else?

3) I've noticed that some of the Mersenne primes are not showing up as primes in your data base, they are only showing up as prp. Can this be updated? (The Mersenne primes up to M1279 are prime, after that they are prp)

Also, I've noticed that your web page doesn't seem to be able to prove primality on numbers with over 600 decimal digits. Is this by design? It seems to run on the numbers for a few minutes and then they drop out of the queue. When I refresh the page for the number it still shows as prp and then it starts trying to prove primality again in the work queue. (and then a few minutes later it drops out of the queue again... )

Also, I've been proving primality of some numbers with primo. Can we upload these certificates to prove that these numbers are prime? Should I generate cert's with another program? Should I PM you the primo certs?