Contribution and Reservation

(53·10²⁰⁰-71)/9 =: 5(8)₁₉₉1_<201>; = 7 · 4159 · [20227695149551364987767969253903372681925218592686734066873523473667739116164218352244320025036543430388104588633561944453985810081025276985844429941568676841578981516466488815611200799948094970937_<197>] SUBMIT/RESERVE

Status

Expression:	(53·10²⁰⁰-71)/9
Composite Factor:	202276951495513649877679692539033726819252185926867340668735 234736677391161642183522443200250365434303881045886335619444 539858100810252769858444299415686768415789815164664888156112 00799948094970937 (197-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 201.72-digit and the GNFS difficulty is 196.31-digit. SNFS must be faster than GNFS. It will take about 22 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 58881_200.
Put the following polynomial file 58881_200.poly in there too.
And then, run "perl factMsieve.pl 58881_200".

58881_200.poly ^*1

n: 20227695149551364987767969253903372681925218592686734066873523473667739116164218352244320025036543430388104588633561944453985810081025276985844429941568676841578981516466488815611200799948094970937
m: 10000000000000000000000000000000000000000
deg: 5
c5: 53
c0: -71
skew: 1.06
type: snfs
lss: 1
rlim: 16100000
alim: 16100000
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 197-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	2500	Dmitry Domanov	Jul 5, 2009
40	3e6	2500 / 1991
45	11e6	0 / 3867
45	11e6	/ 3867
50	43e6	0 / 7451 (1103)
50	43e6	/ 7451 (1103)
55	11e7	0 / 17748 (3091)
55	11e7	/ 17748 (3091)
60	26e7	0 / 42014 (7634)
60	26e7	/ 42014 (7634)

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

echo 20227695149551364987767969253903372681925218592686734066873523473667739116164218352244320025036543430388104588633561944453985810081025276985844429941568676841578981516466488815611200799948094970937 | ecm -n -c 3867 11e6

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

echo 20227695149551364987767969253903372681925218592686734066873523473667739116164218352244320025036543430388104588633561944453985810081025276985844429941568676841578981516466488815611200799948094970937 | ecm -n -c 7451 43e6

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

echo 20227695149551364987767969253903372681925218592686734066873523473667739116164218352244320025036543430388104588633561944453985810081025276985844429941568676841578981516466488815611200799948094970937 | ecm -n -c 17748 11e7

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

echo 20227695149551364987767969253903372681925218592686734066873523473667739116164218352244320025036543430388104588633561944453985810081025276985844429941568676841578981516466488815611200799948094970937 | ecm -n -c 42014 26e7

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