Contribution and Reservation

(16·10²¹²-7)/9 =: 1(7)₂₁₂_<213>; = 3³ · 852851 · 4655561 · [1658320710578251959609155863020212839986768073059968718124202957537408351130782833236092191897020929189373848718325500810977662969514111737300630560271244400040047233797399984643027229624102233498441_<199>] SUBMIT/RESERVE

Status

Expression:	(16·10²¹²-7)/9
Composite Factor:	165832071057825195960915586302021283998676807305996871812420 295753740835113078283323609219189702092918937384871832550081 097766296951411173730063056027124440004004723379739998464302 7229624102233498441 (199-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 213.20-digit and the GNFS difficulty is 198.22-digit. SNFS must be faster than GNFS. It will take about 53 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 17777_212.
Put the following polynomial file 17777_212.poly in there too.
And then, run "perl factMsieve.pl 17777_212".

17777_212.poly ^*1

n: 1658320710578251959609155863020212839986768073059968718124202957537408351130782833236092191897020929189373848718325500810977662969514111737300630560271244400040047233797399984643027229624102233498441
m: 200000000000000000000000000000000000
deg: 6
c6: 25
c0: -7
skew: 0.81
type: snfs
lss: 1
rlim: 25000000
alim: 25000000
lpbr: 29
lpba: 29
mfbr: 57
mfba: 57
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 199-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	4500	Dmitry Domanov	Sep 2, 2009
45	11e6	4500 / 3846
50	43e6	0 / 6437
50	43e6	/ 6437
55	11e7	0 / 17466 (2670)
55	11e7	/ 17466 (2670)
60	26e7	0 / 41942 (7513)
60	26e7	/ 41942 (7513)
65	85e7	0 / 69396 (13587)
65	85e7	/ 69396 (13587)

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

echo 1658320710578251959609155863020212839986768073059968718124202957537408351130782833236092191897020929189373848718325500810977662969514111737300630560271244400040047233797399984643027229624102233498441 | ecm -n -c 6437 43e6

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

echo 1658320710578251959609155863020212839986768073059968718124202957537408351130782833236092191897020929189373848718325500810977662969514111737300630560271244400040047233797399984643027229624102233498441 | ecm -n -c 17466 11e7

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

echo 1658320710578251959609155863020212839986768073059968718124202957537408351130782833236092191897020929189373848718325500810977662969514111737300630560271244400040047233797399984643027229624102233498441 | ecm -n -c 41942 26e7

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

echo 1658320710578251959609155863020212839986768073059968718124202957537408351130782833236092191897020929189373848718325500810977662969514111737300630560271244400040047233797399984643027229624102233498441 | ecm -n -c 69396 85e7

Submit factors

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