Contribution and Reservation

(4·10²⁴⁷-1)/3 =: 1(3)₂₄₇_<248>; = 13 · [1025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641_<247>] SUBMIT/RESERVE

Status

Expression:	(4·10²⁴⁷-1)/3
Composite Factor:	102564102564102564102564102564102564102564102564102564102564 102564102564102564102564102564102564102564102564102564102564 102564102564102564102564102564102564102564102564102564102564 102564102564102564102564102564102564102564102564102564102564 1025641 (247-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 248.51-digit and the GNFS difficulty is 246.01-digit. SNFS must be faster than GNFS. It will take about 800 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 13333_247.
Put the following polynomial file 13333_247.poly in there too.
And then, run "perl factMsieve.pl 13333_247".

13333_247.poly ^*1

n: 1025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641
m: 200000000000000000000000000000000000000000
deg: 6
c6: 5
c0: -8
skew: 1.08
type: snfs
lss: 1
rlim: 97000000
alim: 97000000
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 247-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	1450	Serge Batalov	Nov 14, 2008
		800	Serge Batalov	Nov 29, 2008
		2250 / 0
45	11e6	700	Dmitry Domanov	Jul 11, 2009
		700 / 3940
		/ 3240
50	43e6	0 / 7306 (924)
50	43e6	/ 7306 (924)
55	11e7	0 / 17707 (3031)
55	11e7	/ 17707 (3031)
60	26e7	0 / 42003 (7617)
60	26e7	/ 42003 (7617)

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

echo 1025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641 | ecm -n -c 3240 11e6

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

echo 1025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641 | ecm -n -c 7306 43e6

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

echo 1025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641 | ecm -n -c 17707 11e7

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

echo 1025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641 | ecm -n -c 42003 26e7

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