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-   -   fond of a factor? Bury yourself to become remains (https://www.mersenneforum.org/showthread.php?t=13977)

ckdo 2011-01-07 06:57

[URL="http://www.mersenne.org/report_LL/?exp_lo=39512171&dispdate=1&B1=Get+LL+data"]M39512171[/URL] has a factor: [SIZE=2]23887910757239756825399[/SIZE]

k = 2039*71597*2070643

ckdo 2011-01-10 18:49

M90012887 has a factor: [SIZE=2]439952565941844992833877634700202506740401 :piggie:

k1 = 3*3*5*7*11*19*52177399
k2 = 5*11*71851282747

[/SIZE]

KingKurly 2011-01-10 19:14

[QUOTE=ckdo;245560]M90012887 has a factor: [SIZE=2]439952565941844992833877634700202506740401 :piggie:

k1 = 3*3*5*7*11*19*52177399
k2 = 5*11*71851282747

[/SIZE][/QUOTE]
Goodness, that's a large factor. P-1, I presume?

ckdo 2011-01-10 19:53

[QUOTE=KingKurly;245565]Goodness, that's a large factor. P-1, I presume?[/QUOTE]

TF. First dual 70 bit factors I've seen for an exponent. :coffee:

lorgix 2011-01-12 17:22

[QUOTE=ckdo;245576]TF. First dual 70 bit factors I've seen for an exponent. :coffee:[/QUOTE]

I didn't know that was possible.

Mini-Geek 2011-01-12 17:53

[QUOTE=lorgix;245928]I didn't know that was possible.[/QUOTE]

Why not? There's no reason a number can't have two factors that happen to have the same bit length. There's probably about a 1/4900 (70^(-2)) chance that any particular Mersenne number has two factors that are 70 bits long, so it should be rare, but it's possible.

lorgix 2011-01-12 18:27

[QUOTE=Mini-Geek;245936]Why not? There's no reason a number can't have two factors that happen to have the same bit length. There's probably about a 1/4900 (70^(-2)) chance that any particular Mersenne number has two factors that are 70 bits long, so it should be rare, but it's possible.[/QUOTE]

I [I]thought[/I] it would stop after finding the smaller one.

I wouldn't have been surprised to see a composite factor found by P-1.

axn 2011-01-12 18:43

[QUOTE=Mini-Geek;245936]Why not? There's no reason a number can't have two factors that happen to have the same bit length. There's probably about a 1/4900 (70^(-2)) chance that any particular Mersenne number has two factors that are 70 bits long, so it should be rare, but it's possible.[/QUOTE]

Because prime95 will stop at the first found factor?! :unsure:

ET_ 2011-01-12 19:41

[QUOTE=axn;245958]Because prime95 will stop at the first found factor?! :unsure:[/QUOTE]

Not anymore, IIRC

Luigi

lorgix 2011-01-12 19:59

Why multiply them, instead of reporting them as they are found?

axn 2011-01-12 20:48

[QUOTE=ET_;245974]Not anymore, IIRC

Luigi[/QUOTE]

Huh? It used to be that, once upon a time, p95 used to go ahead with TF even if a factor was found, just to make sure that no _smaller_ factor was missed. Then, that was removed. You mean to say that this (mis)feature has been reintroduced?!


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