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Old 2007-05-16, 13:51   #4
Greenbank
 
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Jul 2005

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But what about a case such as 123012031 ?

which is 4523 * 27197

Depending on the sigma I can discover either factor:-

GMP-ECM 6.1 [powered by GMP 4.1.4] [ECM]
Input number is 123012031 (9 digits)
Using B1=100, B2=2046, polynomial x^1, sigma=3741624400
Step 1 took 0ms
********** Factor found in step 1: 4523
Found probable prime factor of 4 digits: 4523
Probable prime cofactor 27197 has 5 digits

GMP-ECM 6.1 [powered by GMP 4.1.4] [ECM]
Input number is 123012031 (9 digits)
Using B1=100, B2=2046, polynomial x^1, sigma=3887925014
Step 1 took 0ms
********** Factor found in step 1: 27197
Found probable prime factor of 5 digits: 27197
Probable prime cofactor 4523 has 4 digits
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