Contribution and Reservation

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 183.75-digit and the GNFS difficulty is 124.23-digit. GNFS must be faster than SNFS. It will take about 3 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 62227_182.
2. Put the following polynomial file 62227_182.poly in there too.
3. And then, run "perl factMsieve.pl 62227_182".

# Murphy_E = 1.588709e-10, selected by Jeff Gilchrist
n: 16857152605764005065047232676396102366871417751924711712204360137910738853018733972405664108283513247694184519411936056181109
Y0: -988945101806413388444541
Y1: 46619356619399
c0: 345252897099515749349880144740
c1: 16744884629216264921754598
c2: -441036489356752317482
c3: -24071128396711
c4: 13578735000
c5: 17820
skew: 171252.46
type: gnfs
# selected mechanically
rlim: 6800000
alim: 6800000
lpbr: 27
lpba: 27
mfbr: 52
mfba: 52
rlambda: 2.5
alambda: 2.5

*1 These parameters were not fully adjusted. The approximate expressions which were used for making the parameters are: d=log10(n); time=10^(d/21-4)[hours]; rlim=round(3*10^(d/37+3)); lpbr=floor(d/18+21); mfbr=floor(d/5+28); rlambda=floor(d/26+21)/10;

See also

• How to contribute your factors

The efforts by ECM to find small factors of this 125-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)