Contribution and Reservation

(16·10²⁰⁴-61)/9 =: 1(7)₂₀₃1_<205>; = 15193 · 30259 · 42402071 · [91199465939262957014453301415352275982936112553092972842134854009173370399862056645203863554210681162010186392008374136296116283472153026753275014021217505791515685112718096980495275936023_<188>] SUBMIT/RESERVE

Status

Expression:	(16·10²⁰⁴-61)/9
Composite Factor:	911994659392629570144533014153522759829361125530929728421348 540091733703998620566452038635542106811620101863920083741362 961162834721530267532750140212175057915156851127180969804952 75936023 (188-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 205.90-digit and the GNFS difficulty is 187.96-digit. SNFS must be faster than GNFS. It will take about 30 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 17771_204.
Put the following polynomial file 17771_204.poly in there too.
And then, run "perl factMsieve.pl 17771_204".

17771_204.poly ^*1

n: 91199465939262957014453301415352275982936112553092972842134854009173370399862056645203863554210681162010186392008374136296116283472153026753275014021217505791515685112718096980495275936023
m: 100000000000000000000000000000000000000000
deg: 5
c5: 8
c0: -305
skew: 2.07
type: snfs
lss: 1
rlim: 18900000
alim: 18900000
lpbr: 29
lpba: 29
mfbr: 56
mfba: 56
rlambda: 2.6
alambda: 2.6

*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 188-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 7, 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 91199465939262957014453301415352275982936112553092972842134854009173370399862056645203863554210681162010186392008374136296116283472153026753275014021217505791515685112718096980495275936023 | ecm -n -c 204 5e4

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

echo 91199465939262957014453301415352275982936112553092972842134854009173370399862056645203863554210681162010186392008374136296116283472153026753275014021217505791515685112718096980495275936023 | ecm -n -c 430 25e4

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

echo 91199465939262957014453301415352275982936112553092972842134854009173370399862056645203863554210681162010186392008374136296116283472153026753275014021217505791515685112718096980495275936023 | ecm -n -c 904 1e6

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

echo 91199465939262957014453301415352275982936112553092972842134854009173370399862056645203863554210681162010186392008374136296116283472153026753275014021217505791515685112718096980495275936023 | ecm -n -c 2350 3e6

Submit factors

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