Contribution and Reservation

4·10²⁴⁹-9 =: 3(9)₂₄₈1_<250>; = 13 · [307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307_<249>] SUBMIT/RESERVE

Status

Expression:	4·10²⁴⁹-9
Composite Factor:	307692307692307692307692307692307692307692307692307692307692 307692307692307692307692307692307692307692307692307692307692 307692307692307692307692307692307692307692307692307692307692 307692307692307692307692307692307692307692307692307692307692 307692307 (249-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 249.90-digit and the GNFS difficulty is 248.49-digit. SNFS must be faster than GNFS. It will take about 891 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 39991_249.
Put the following polynomial file 39991_249.poly in there too.
And then, run "perl factMsieve.pl 39991_249".

39991_249.poly ^*1

n: 307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307
m: 200000000000000000000000000000000000000000
deg: 6
c6: 125
c0: -18
skew: 0.72
type: snfs
lss: 1
rlim: 102000000
alim: 102000000
lpbr: 30
lpba: 30
mfbr: 62
mfba: 62
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;

Efforts by ECM

The efforts by ECM to find small factors of this 249-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)

Level	B1	Reported runs Total / Required runs (Required runs for lower level)	Name
40	3e6	660	Serge Batalov	Nov 7, 2008
		85	Serge Batalov	Nov 27, 2008
		107	Serge Batalov	Nov 28, 2008
		852 / 0
45	11e6	180	Serge Batalov	Nov 7, 2008
		250	Serge Batalov	Nov 28, 2008
		150	Serge Batalov	Nov 28, 2008
		580 / 2782
		/ 2202
50	43e6	430	Serge Batalov	Nov 28, 2008
		430 / 7391 (1058)
		/ 6961 (628)
55	11e7	0 / 17573 (2888)
55	11e7	/ 17573 (2888)
60	26e7	0 / 41957 (7559)
60	26e7	/ 41957 (7559)

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

echo 307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307 | ecm -n -c 2202 11e6

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

echo 307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307 | ecm -n -c 6961 43e6

Command line to find prime factors up to about 55-digit

echo 307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307 | ecm -n -c 17573 11e7

Command line to find prime factors up to about 60-digit

echo 307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307692307 | ecm -n -c 41957 26e7

Submit factors

Make reservation

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