mersenneforum.org Factoring database
 Register FAQ Search Today's Posts Mark Forums Read

 2011-01-16, 13:34 #1013 rekcahx   Oct 2009 Oulu, Finland 2×3×5 Posts I found a problem from the DB. http://factordb.com/index.php?id=1100000000217043267 This 7 digit number 1210012 is fully factored, but its status is still "C".
 2011-01-16, 13:36 #1014 lorgix     Sep 2010 Scandinavia 3·5·41 Posts It's the '%' again. It has been discussed earlier in the thread.
2011-01-16, 13:38   #1015
henryzz
Just call me Henry

"David"
Sep 2007
Cambridge (GMT/BST)

2·2,897 Posts

Quote:
 Originally Posted by lorgix It's the '%' again. It has been discussed earlier in the thread.
Yes http://factordb.com/index.php?query=1210012 is correct.

 2011-01-16, 20:22 #1016 wblipp     "William" May 2003 New Haven 44708 Posts Is there a way to get the database's known factorizations of the form p^q-1, p an odd prime, q a prime?
2011-01-16, 20:53   #1017
rekcahx

Oct 2009
Oulu, Finland

111102 Posts

Quote:
 Originally Posted by wblipp Is there a way to get the database's known factorizations of the form p^q-1, p an odd prime, q a prime?
Maybe.
In example: http://factordb.com/index.php?query=x^3-1&use=x&x=2&VP=on&OD=on&PR=on&FF=on&PRP=on&CF=on&U=on&C=on&perpage=200&format=1&sent=Show

2011-01-17, 09:56   #1018
kar_bon

Mar 2006
Germany

B3216 Posts

Quote:
 Originally Posted by wblipp Is there a way to get the database's known factorizations of the form p^q-1, p an odd prime, q a prime?
In the factorDB see the link Factor tables and from the listed tables choose Others.

There're several terms listed, including Cunningham numbers b^n-1.

Choose 'Show' to get the screen of this table.
Deselect "b is even" and "b is composite", n is set to 1 by default (fill in a different value if needed) and click 'Show' to update the results.

 2011-01-17, 18:48 #1019 Andi47     Oct 2004 Austria 2·17·73 Posts Sequence 84822 is broken, see here: http://www.mersenneforum.org/showthread.php?t=14859
2011-01-17, 20:53   #1020
wblipp

"William"
May 2003
New Haven

23·5·59 Posts

Quote:
 Originally Posted by kar_bon In the factorDB see the link Factor tables and from the listed tables choose Others. There're several terms listed, including Cunningham numbers b^n-1. Choose 'Show' to get the screen of this table. Deselect "b is even" and "b is composite", n is set to 1 by default (fill in a different value if needed) and click 'Show' to update the results.
It looks like if a page would require numbers that have not been previously considered, they are automatically generated and trial factored - is that right?

 2011-01-17, 22:08 #1021 warut   Dec 2009 89 Posts I've noticed that the database erroneously omits some small factors of the following 77-digit numbers: Code:  80978084394598568390520920252440060895670346459831516622284554518849503146397 82609404176288347510975214065063503631619108607371480044587508148396968704911 88236918639719858997946921372584311423090252002347982879826766163694271697843 88894857952232839709785628818457172955757575436001096904562755715875193607509 92250106588933435730861605431146390431716761868772836262451636991161111409211 96219970786531934764768710647149833037379504561939264511368166182316972958369
2011-01-17, 23:42   #1022
warut

Dec 2009

89 Posts

Quote:
 Originally Posted by wblipp It looks like if a page would require numbers that have not been previously considered, they are automatically generated and trial factored - is that right?
Yes.

 2011-01-18, 06:17 #1023 mdettweiler A Sunny Moo     Aug 2007 USA (GMT-5) 3·2,083 Posts @Syd: just curious, what program are you using for N-1 and N+1 tests? I tried putting in a known small-ish prime with a trivial N+1 factorization (50633872*3^25032-1) to have the DB take a whack at it, and it somewhere in the vicinity of 12-20 minutes to do the N+1 test. My computer took just 90 seconds to do it even with the old (1.2) version of PFGW, so I'm guessing you must be using something different.

 Similar Threads Thread Thread Starter Forum Replies Last Post 3.14159 Miscellaneous Math 325 2016-04-09 17:45 Mini-Geek Factoring 5 2009-07-01 11:51 HiddenWarrior Data 1 2004-03-29 03:53 Prime95 PrimeNet 1 2003-01-18 00:49 Joe O Lounge 35 2002-09-06 20:19

All times are UTC. The time now is 21:48.

Thu Jan 21 21:48:35 UTC 2021 up 49 days, 17:59, 0 users, load averages: 2.70, 2.33, 2.32