Thread: Small factors
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Old 2006-11-15, 19:41   #4
axn's Avatar
Jun 2003

2·3·19·43 Posts

Originally Posted by Kees View Post
and I suppose it also truncates the "bit"-length ?
Apparently so

Here are a bunch of factors truncated in the report to 31 digits.
32492333 103   F  8316861747465793506084499558121  09-Nov-06 19:21  cathas         CE8CFA671
36411527 103   F  7263852526156696381869159290527  11-Nov-06 22:30  blackguard     carbon
36773851 103   F  9075527700594867141608327604401  14-Nov-06 17:53  S517661        C7F0535E6
36534737 101   F  3109119109442520160313833481551  11-Nov-06 13:06  S152209        CFC460636
36626063 101   F  1875630778194861452245225486337  01-Nov-06 09:11  abienvenu      betaweb1
36627907 100   F  1746551189471568749237051498287  03-Nov-06 20:11  mnrcrl42       silvia
What happens is sometimes P-1 finds two factors in a single run and reports it as a huge composite. The report truncates them, but the DB has the actual value. So I guess you could ask George to give you the real values

PS:- The truncated factors are clearly not valid, since a factor of 2^p-1 must be of the form 2kp+1. So the smallest possible factor is 2p+1. If you see anything smaller, obviously it is not correct.
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