Contribution and Reservation

(64·10²³⁹+53)/9 =: 7(1)₂₃₈7_<240>; = 3² · 11 · 250598967794391156254550409_<27> · [28663088996309171528140485054027154277033677855462679486325734293197606844008758852822578666097812052206553900399642591762004425576947643905586985914761699503385497196569271955978608657621588112226339555759862487_<212>] SUBMIT/RESERVE

Status

Expression:	(64·10²³⁹+53)/9
Composite Factor:	286630889963091715281404850540271542770336778554626794863257 342931976068440087588528225786660978120522065539003996425917 620044255769476439055869859147616995033854971965692719559786 08657621588112226339555759862487 (212-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 241.51-digit and the GNFS difficulty is 211.46-digit. SNFS must be faster than GNFS. It will take about 468 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 71117_239.
Put the following polynomial file 71117_239.poly in there too.
And then, run "perl factMsieve.pl 71117_239".

71117_239.poly ^*1

n: 28663088996309171528140485054027154277033677855462679486325734293197606844008758852822578666097812052206553900399642591762004425576947643905586985914761699503385497196569271955978608657621588112226339555759862487
m: 10000000000000000000000000000000000000000
deg: 6
c6: 32
c0: 265
skew: 1.42
type: snfs
lss: 1
rlim: 74000000
alim: 74000000
lpbr: 30
lpba: 30
mfbr: 61
mfba: 61
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 212-digit composite number so far are as follows. According to the reports, unknown prime factors of this composite number are probably 20-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
20	11e3	74	Max Dettweiler	Mar 6, 2009
20	11e3	74 / 74
25	5e4	0 / 204
25	5e4	/ 204
30	25e4	0 / 430 (48)
30	25e4	/ 430 (48)
35	1e6	0 / 904 (118)
35	1e6	/ 904 (118)
40	3e6	0 / 2350 (322)
40	3e6	/ 2350 (322)

Command line to find prime factors up to about 25-digit

echo 28663088996309171528140485054027154277033677855462679486325734293197606844008758852822578666097812052206553900399642591762004425576947643905586985914761699503385497196569271955978608657621588112226339555759862487 | ecm -n -c 204 5e4

Command line to find prime factors up to about 30-digit

echo 28663088996309171528140485054027154277033677855462679486325734293197606844008758852822578666097812052206553900399642591762004425576947643905586985914761699503385497196569271955978608657621588112226339555759862487 | ecm -n -c 430 25e4

Command line to find prime factors up to about 35-digit

echo 28663088996309171528140485054027154277033677855462679486325734293197606844008758852822578666097812052206553900399642591762004425576947643905586985914761699503385497196569271955978608657621588112226339555759862487 | ecm -n -c 904 1e6

Command line to find prime factors up to about 40-digit

echo 28663088996309171528140485054027154277033677855462679486325734293197606844008758852822578666097812052206553900399642591762004425576947643905586985914761699503385497196569271955978608657621588112226339555759862487 | ecm -n -c 2350 3e6

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