You got that right ;-)

[QUOTE=Batalov;457449]You got that right ;-)[/QUOTE]
Which right? Why he has some rights which I don't have? Is this constitutional? :shock:

[QUOTE=Xyzzy;457034]Wouldn't it be much more efficient to run ECM work on the 1187 digit composite rather than the original number?[/QUOTE]

Actually, it's only a 1133-digit cofactor, you're forgetting the 54-digit largest factor 568630647535356955169033410940867804839360742060818433

And not "much" more efficient, since F12 itself is 1234 digits long.

In any case, if you supply the list of known factors in double quotes at the end of the ECM2= line, then mprime has all the information it needs and presumably does its work in the most efficient way possible. I don't know if the algorithm works faster on the original number or the cofactor.

Today someone discovered a new 44-digit factor of [M]M2957[/M], the third-known factor of that exponent. The cofactor is composite, according to factordb

[QUOTE=GP2;457464]Actually, it's only a 1133-digit cofactor, you're forgetting the 54-digit largest factor 568630647535356955169033410940867804839360742060818433[/QUOTE]It would be difficult for us to [URL="http://caramel.loria.fr/f12.txt"]forget that factor[/URL].

Our error is typing too fast and thinking too little.

[QUOTE=GP2;457464]And not "much" more efficient, since F12 itself is 1234 digits long.[/QUOTE]F12 is 101 times bigger than the C1133. That seems like a big difference, but we are willing to be educated!

:mike:

[QUOTE=Xyzzy;457481]
F12 is 101 times bigger than the C1133. That seems like a big difference, but we are willing to be educated![/QUOTE]

Are you sure?

F13 is roughly F12 times bigger than F12... no wonder it's taking so long to find more Fermat factors.:confused:

[QUOTE=Xyzzy;457481]It would be difficult for us to [URL="http://caramel.loria.fr/f12.txt"]forget that factor[/URL].
[/QUOTE]
That was my thinking too, haha.... but you were faster to post it.

[QUOTE=GP2;457488]Are you sure?

F13 is roughly F12 times bigger than F12... no wonder it's taking so long to find more Fermat factors.:confused:[/QUOTE]

He wanna say "digits" not "times". Typo.

P-1 found a factor in stage #2, B1=675000, B2=12825000.
UID: Jwb52z/Clay, M81180581 has a factor: 97246609841457762906841 (P-1, B1=675000, B2=12825000)

76.364 bits.

P-1 found a factor in stage #1, B1=680000.
UID: Jwb52z/Clay, M81309119 has a factor: 212788775459776906189271 (P-1, B1=680000)

77.494 bits.

P-1 found a factor in stage #1, B1=680000.
UID: Jwb52z/Clay, M81282431 has a factor: 465065881821653916530959 (P-1, B1=680000),

78.622 bits.