Contribution and Reservation

(88·10¹⁹⁷-7)/9 =: 9(7)₁₉₇_<198>; = 47 · 61 · 12150092320841_<14> · 39579394802884247_<17> · 120780957158617319735656378500678509_<36> · [5871719163515225280922211088120438405575691242148159445644927132369821177548971534618963281375524980385790625213433048301365617017_<130>] (Serge Batalov / GMP-ECM 6.2.1 B1=3000000, sigma=3923837933 for P36 / Oct 21, 2008) SUBMIT/RESERVE

Status

Expression:	(88·10¹⁹⁷-7)/9
Composite Factor:	587171916351522528092221108812043840557569124214815944564492 713236982117754897153461896328137552498038579062521343304830 1365617017 (130-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.

GNFS

Use GGNFS and/or Msieve if GMP-ECM cannot find a factor. The SNFS difficulty of this composite number is 198.94-digit and the GNFS difficulty is 129.77-digit. GNFS must be faster than SNFS. It will take about 6 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 97777_197.
Put the following polynomial file 97777_197.poly in there too.
And then, run "perl factMsieve.pl 97777_197".

97777_197.poly ^*1

# Murphy_E = 7.881737e-11, selected by Jeff Gilchrist
n: 5871719163515225280922211088120438405575691242148159445644927132369821177548971534618963281375524980385790625213433048301365617017
Y0: -10491226194789455755296759
Y1: 186651553525933
c0: -169965754597057205412952998548800
c1: -676066635901011959672812056
c2: 9339493862388733982498
c3: 12593531036882625
c4: -47555103760
c5: 46200
skew: 369676.06
type: gnfs
# selected mechanically
rlim: 9600000
alim: 9600000
lpbr: 28
lpba: 28
mfbr: 53
mfba: 53
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;

Efforts by ECM

The efforts by ECM to find small factors of this 130-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	500	Erik Branger	Feb 1, 2009
		1850	Wataru Sakai	Aug 23, 2009
		2350 / 2350
45	11e6	0 / 3961
45	11e6	/ 3961
50	43e6	0 / 7465 (1129)
50	43e6	/ 7465 (1129)
55	11e7	0 / 17751 (3097)
55	11e7	/ 17751 (3097)
60	26e7	0 / 42014 (7636)
60	26e7	/ 42014 (7636)

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

echo 5871719163515225280922211088120438405575691242148159445644927132369821177548971534618963281375524980385790625213433048301365617017 | ecm -n -c 3961 11e6

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

echo 5871719163515225280922211088120438405575691242148159445644927132369821177548971534618963281375524980385790625213433048301365617017 | ecm -n -c 7465 43e6

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

echo 5871719163515225280922211088120438405575691242148159445644927132369821177548971534618963281375524980385790625213433048301365617017 | ecm -n -c 17751 11e7

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

echo 5871719163515225280922211088120438405575691242148159445644927132369821177548971534618963281375524980385790625213433048301365617017 | ecm -n -c 42014 26e7

Contribution and Reservation

Status

How to factor it

ECM, P-1, P+1

GNFS

See also

Efforts by ECM

Submit polynomial for GNFS

Submit factors

Make reservation