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.

SNFS

Use GGNFS and/or Msieve if GMP-ECM cannot find a factor. The SNFS difficulty of this composite number is 237.81-digit and the GNFS difficulty is 184.19-digit. SNFS must be faster than GNFS. It will take about 352 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 71117_236.
2. Put the following polynomial file 71117_236.poly in there too.
3. And then, run "perl factMsieve.pl 71117_236".

n: 15546326742142275797343802733855931211964187662623718039519045945410959794410303852402574597376122760199834255719754439546665593662708368862695746542115188846097476249599680897257390819
m: 2000000000000000000000000000000000000000
deg: 6
c6: 100
c0: 53
skew: 0.90
type: snfs
lss: 1
rlim: 64000000
alim: 64000000
lpbr: 30
lpba: 30
mfbr: 60
mfba: 60
rlambda: 2.7
alambda: 2.7

*1 These parameters were not fully adjusted. The approximate expressions which were used for making the parameters are: deg=expt<=105?4:expt<=210?5:6 or expt<=144?4:6; d=log10(c[deg])+deg*log10(m)[digits]; time=10^(d/30-4)[hours]; skew=|c0/c[deg]|^(1/deg); rlim=round(7*10^(d/60+3)); lpbr=floor(d/25+21); mfbr=floor(d/8+31); rlambda=floor(d/25+18)/10;

See also

• How to contribute your factors

The efforts by ECM to find small factors of this 185-digit composite number so far are as follows. According to the reports, unknown prime factors of this composite number are probably 20-digit or more. Please report your efforts by ECM. (Anonymous reports are not acceptable)