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(62·10187-71)/9 =
6(8)1861<188>
= 173 · 37754149 · 967824333513549013<18> · 216802388339074258698275400269<30> · [50266401073944387005872937866183784917399113571780638731571774164778399859981921931914065676985560744592344630601055339358805564449<131>] (Makoto Kamada / GMP-ECM 6.2.3 B1=1e6, sigma=3382327869 for P30 / Nov 9, 2009) SUBMIT/RESERVE

Status

Expression:(62·10187-71)/9
Composite Factor:502664010739443870058729378661837849173991135717806387315717
741647783998599819219319140656769855607445923446306010553393
58805564449
(131-digit)
Status:Not factored. Not reserved. You can submit its factors or reserve it for submitting in the future.

How to factor it

ECM, P-1, P+1

Look for prime factors by GMP-ECM first. Refer to the section "Efforts by ECM". Not only ECM but also P-1/P+1 may be helpful.

GNFS

Use GGNFS and/or Msieve if GMP-ECM cannot find a factor. The SNFS difficulty of this composite number is 189.39-digit and the GNFS difficulty is 130.70-digit. GNFS must be faster than SNFS. It will take about 7 CPU-days to factor this composite number on 64-bit Opteron-2600MHz.

  1. Put factMsieve.pl to which $GGNFS_BIN_PATH and $NUM_CPUS were modified properly in the working directory 68881_187.
  2. Put the following composite number file 68881_187.n in there too.
  3. And then, run "perl factMsieve.pl 68881_187".
68881_187.n
n: 50266401073944387005872937866183784917399113571780638731571774164778399859981921931914065676985560744592344630601055339358805564449

See also


Efforts by ECM

The efforts by ECM to find small factors of this 131-digit composite number so far are as follows. According to the reports, unknown prime factors of this composite number are probably 40-digit or more. Please report your efforts by ECM. (Anonymous reports are not acceptable)

LevelB1Reported runs
Total / Required runs
(Required runs for lower level)		Name 
403e62318Wataru SakaiNov 12, 2009
2318 / 2318  
4511e60 / 3963  
/ 3963
5043e60 / 7465 (1130)  
/ 7465 (1130)  
5511e70 / 17751 (3097)  
/ 17751 (3097)  
6026e70 / 42014 (7636)  
/ 42014 (7636)  
Command line to find prime factors up to about 45-digit
echo 50266401073944387005872937866183784917399113571780638731571774164778399859981921931914065676985560744592344630601055339358805564449 | ecm -n -c 3963 11e6
Command line to find prime factors up to about 50-digit
echo 50266401073944387005872937866183784917399113571780638731571774164778399859981921931914065676985560744592344630601055339358805564449 | ecm -n -c 7465 43e6
Command line to find prime factors up to about 55-digit
echo 50266401073944387005872937866183784917399113571780638731571774164778399859981921931914065676985560744592344630601055339358805564449 | ecm -n -c 17751 11e7
Command line to find prime factors up to about 60-digit
echo 50266401073944387005872937866183784917399113571780638731571774164778399859981921931914065676985560744592344630601055339358805564449 | ecm -n -c 42014 26e7

Submit polynomial for GNFS

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