Contribution and Reservation

(8·10²⁰⁷+7)/3 =: 2(6)₂₀₆9_<208>; = 563 · 25771 · 28097 · [6541376027123957670494783179083898870845505504901981406927544296429518380566407671285541222297594259643663344598261364445921908339669127219536640194545851389923155211474929976541506999609569630749_<196>] SUBMIT/RESERVE

Status

Expression:	(8·10²⁰⁷+7)/3
Composite Factor:	654137602712395767049478317908389887084550550490198140692754 429642951838056640767128554122229759425964366334459826136444 592190833966912721953664019454585138992315521147492997654150 6999609569630749 (196-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.

SNFS

Use GGNFS and/or Msieve if GMP-ECM cannot find a factor. The SNFS difficulty of this composite number is 207.90-digit and the GNFS difficulty is 195.82-digit. SNFS must be faster than GNFS. It will take about 35 CPU-days to factor this composite number on 64-bit Opteron-2600MHz.

Put factMsieve.pl to which $GGNFS_BIN_PATH and $NUM_CPUS were modified properly in the working directory 26669_207.
Put the following polynomial file 26669_207.poly in there too.
And then, run "perl factMsieve.pl 26669_207".

26669_207.poly ^*1

n: 6541376027123957670494783179083898870845505504901981406927544296429518380566407671285541222297594259643663344598261364445921908339669127219536640194545851389923155211474929976541506999609569630749
m: 200000000000000000000000000000000000000000
deg: 5
c5: 25
c0: 7
skew: 0.78
type: snfs
lss: 1
rlim: 20000000
alim: 20000000
lpbr: 29
lpba: 29
mfbr: 56
mfba: 56
rlambda: 2.6
alambda: 2.6

*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;

Efforts by ECM

The efforts by ECM to find small factors of this 196-digit composite number so far are as follows. According to the reports, unknown prime factors of this composite number are probably 30-digit or more. Please report your efforts by ECM. (Anonymous reports are not acceptable)

Level	B1	Reported runs Total / Required runs (Required runs for lower level)	Name
30	25e4	0 / 0
35	1e6	118	Makoto Kamada	Oct 14, 2009
		118 / 904
		/ 786
40	3e6	0 / 2318 (280)
40	3e6	/ 2318 (280)
45	11e6	0 / 4475 (672)
45	11e6	/ 4475 (672)
50	43e6	0 / 7553 (1276)
50	43e6	/ 7553 (1276)

Command line to find prime factors up to about 35-digit

echo 6541376027123957670494783179083898870845505504901981406927544296429518380566407671285541222297594259643663344598261364445921908339669127219536640194545851389923155211474929976541506999609569630749 | ecm -n -c 786 1e6

Command line to find prime factors up to about 40-digit

echo 6541376027123957670494783179083898870845505504901981406927544296429518380566407671285541222297594259643663344598261364445921908339669127219536640194545851389923155211474929976541506999609569630749 | ecm -n -c 2318 3e6

Command line to find prime factors up to about 45-digit

echo 6541376027123957670494783179083898870845505504901981406927544296429518380566407671285541222297594259643663344598261364445921908339669127219536640194545851389923155211474929976541506999609569630749 | ecm -n -c 4475 11e6

Command line to find prime factors up to about 50-digit

echo 6541376027123957670494783179083898870845505504901981406927544296429518380566407671285541222297594259643663344598261364445921908339669127219536640194545851389923155211474929976541506999609569630749 | ecm -n -c 7553 43e6

Submit factors

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