Contribution and Reservation

(16·10²³⁷-7)/9 =: 1(7)₂₃₇_<238>; = 50264843 · [35368215071869970384226163359901030184810838417972931453854889744264749375180138885100621477675316279765914672761989483937665492713819433948650307686781748781703700492564510303509309235836621986022671507752999005244635455795172339_<230>] SUBMIT/RESERVE

Status

Expression:	(16·10²³⁷-7)/9
Composite Factor:	353682150718699703842261633599010301848108384179729314538548 897442647493751801388851006214776753162797659146727619894839 376654927138194339486503076867817487817037004925645103035093 09235836621986022671507752999005244635455795172339 (230-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 238.20-digit and the GNFS difficulty is 229.55-digit. SNFS must be faster than GNFS. It will take about 363 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 17777_237.
Put the following polynomial file 17777_237.poly in there too.
And then, run "perl factMsieve.pl 17777_237".

17777_237.poly ^*1

n: 35368215071869970384226163359901030184810838417972931453854889744264749375180138885100621477675316279765914672761989483937665492713819433948650307686781748781703700492564510303509309235836621986022671507752999005244635455795172339
m: 2000000000000000000000000000000000000000
deg: 6
c6: 250
c0: -7
skew: 0.55
type: snfs
lss: 1
rlim: 65000000
alim: 65000000
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;

Efforts by ECM

The efforts by ECM to find small factors of this 230-digit composite number so far are as follows. According to the reports, unknown prime factors of this composite number are probably 45-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
45	11e6	4500	Dmitry Domanov	Sep 2, 2009
45	11e6	4500 / 0
50	43e6	1331	Wataru Sakai	Oct 15, 2009
		1331 / 6439
		/ 5108
55	11e7	0 / 16991 (2119)
55	11e7	/ 16991 (2119)
60	26e7	0 / 41786 (7309)
60	26e7	/ 41786 (7309)
65	85e7	0 / 69364 (13537)
65	85e7	/ 69364 (13537)

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

echo 35368215071869970384226163359901030184810838417972931453854889744264749375180138885100621477675316279765914672761989483937665492713819433948650307686781748781703700492564510303509309235836621986022671507752999005244635455795172339 | ecm -n -c 5108 43e6

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

echo 35368215071869970384226163359901030184810838417972931453854889744264749375180138885100621477675316279765914672761989483937665492713819433948650307686781748781703700492564510303509309235836621986022671507752999005244635455795172339 | ecm -n -c 16991 11e7

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

echo 35368215071869970384226163359901030184810838417972931453854889744264749375180138885100621477675316279765914672761989483937665492713819433948650307686781748781703700492564510303509309235836621986022671507752999005244635455795172339 | ecm -n -c 41786 26e7

Command line to find prime factors up to about 65-digit

echo 35368215071869970384226163359901030184810838417972931453854889744264749375180138885100621477675316279765914672761989483937665492713819433948650307686781748781703700492564510303509309235836621986022671507752999005244635455795172339 | ecm -n -c 69364 85e7

Submit factors

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