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Old 2011-01-07, 06:57   #45
ckdo
 
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M39512171 has a factor: 23887910757239756825399

k = 2039*71597*2070643
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Old 2011-01-10, 18:49   #46
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M90012887 has a factor: 439952565941844992833877634700202506740401

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

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Old 2011-01-10, 19:14   #47
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Quote:
Originally Posted by ckdo View Post
M90012887 has a factor: 439952565941844992833877634700202506740401

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

Goodness, that's a large factor. P-1, I presume?
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Old 2011-01-10, 19:53   #48
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Quote:
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Goodness, that's a large factor. P-1, I presume?
TF. First dual 70 bit factors I've seen for an exponent.
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Old 2011-01-12, 17:22   #49
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Quote:
Originally Posted by ckdo View Post
TF. First dual 70 bit factors I've seen for an exponent.
I didn't know that was possible.
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Old 2011-01-12, 17:53   #50
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Quote:
Originally Posted by lorgix View Post
I didn't know that was possible.
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.
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Old 2011-01-12, 18:27   #51
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Quote:
Originally Posted by Mini-Geek View Post
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.
I thought it would stop after finding the smaller one.

I wouldn't have been surprised to see a composite factor found by P-1.
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Old 2011-01-12, 18:43   #52
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Quote:
Originally Posted by Mini-Geek View Post
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.
Because prime95 will stop at the first found factor?!
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Old 2011-01-12, 19:41   #53
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Quote:
Originally Posted by axn View Post
Because prime95 will stop at the first found factor?!
Not anymore, IIRC

Luigi
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Old 2011-01-12, 19:59   #54
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Why multiply them, instead of reporting them as they are found?
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Old 2011-01-12, 20:48   #55
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Originally Posted by ET_ View Post
Not anymore, IIRC

Luigi
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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