Contribution and Reservation

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

Status

Expression:	(4·10²⁴⁷-1)/3
Composite Factor:	102564102564102564102564102564102564102564102564102564102564 102564102564102564102564102564102564102564102564102564102564 102564102564102564102564102564102564102564102564102564102564 102564102564102564102564102564102564102564102564102564102564 1025641 (247-digit)
Status:	Not factored. Reserved by Lionel Debroux 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.

NFS

Use GGNFS and/or Msieve if GMP-ECM cannot find a factor. The SNFS difficulty of this composite number is 247.60-digit and the GNFS difficulty is 246.01-digit. SNFS must be faster than GNFS. It will take about 747 CPU-days to factor this composite number on 64-bit Opteron-2600MHz.

Steps of SNFS

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

n: 1025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641
m: 100000000000000000000000000000000000000000
deg: 6
c6: 40
c0: -1
skew: 0.54
type: snfs
lss: 1
rlim: 94000000
alim: 94000000
lpbr: 30
lpba: 30
mfbr: 61
mfba: 61
rlambda: 2.7
alambda: 2.7

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 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	700	Dmitry Domanov	Jul 11, 2009
45	11e6	700 / 432
50	43e6	1000	yoyo@home	Jan 15, 2010
		1000 / 7306
		/ 6306
55	11e7	0 / 17350 (2616)
55	11e7	/ 17350 (2616)
60	26e7	0 / 41886 (7463)
60	26e7	/ 41886 (7463)
65	85e7	0 / 69382 (13569)
65	85e7	/ 69382 (13569)

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

echo 1025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641 | ecm -n -c 6306 43e6

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

echo 1025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641 | ecm -n -c 17350 11e7

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

echo 1025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641 | ecm -n -c 41886 26e7

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

echo 1025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641025641 | ecm -n -c 69382 85e7

Submit factors

Cancel reservation

Back to Factorizations of near-repdigit numbers