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 202.74-digit and the GNFS difficulty is 124.08-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 61117_201.
2. Put the following polynomial file 61117_201.poly in there too.
3. And then, run "perl factMsieve.pl 61117_201".

# Murphy_E = 1.689413e-10, selected by Jeff Gilchrist
n: 12092333369161073721453095497369483934473764519498218736238482790936465340160389049119166372609930051353777385455408331203957
Y0: -900691105519994157906063
Y1: 30756511058759
c0: 7374718785776876741395604449696
c1: -124029579845001853330871254
c2: -332545945996177963197
c3: -2598363417318266
c4: 789659216
c5: 20400
skew: 305447.87
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 35-digit or more. Please report your efforts by ECM. (Anonymous reports are not acceptable)