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 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 23·5·59 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

2×3×5 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

2·1,433 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 46628 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

8910 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.

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