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 190.85-digit and the GNFS difficulty is 124.81-digit. GNFS must be faster than SNFS. It will take about 4 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 46663_189.
2. Put the following polynomial file 46663_189.poly in there too.
3. And then, run "perl factMsieve.pl 46663_189".

# Murphy_E = 1.550342e-10, selected by Jeff Gilchrist
n: 64978130902253701431603911949117122821858993709530816111968184585992575118949597873699551224758662423230331218602852749861233
Y0: -1215598652283778943922551
Y1: 47683749565433
c0: 788727315350780521133097588480
c1: 55972769251044317414382168
c2: -180553814121381247850
c3: -11773977496866361
c4: 6828480658
c5: 24480
skew: 189567.7
type: gnfs
# selected mechanically
rlim: 7100000
alim: 7100000
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)