Contribution and Reservation

(5·10¹⁹⁶-17)/3 =: 1(6)₁₉₅1_<197>; = 732216971 · [22761923482741383587333796810708811974076283280610641113734396995650441795983265548575582887803165472747102807409071465876562790930813684550158653269819754924345596281824867272390312661391_<188>] SUBMIT/RESERVE

Status

Expression:	(5·10¹⁹⁶-17)/3
Composite Factor:	227619234827413835873337968107088119740762832806106411137343 969956504417959832655485755828878031654727471028074090714658 765627909308136845501586532698197549243455962818248672723903 12661391 (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 196.70-digit and the GNFS difficulty is 187.36-digit. SNFS must be faster than GNFS. It will take about 15 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 16661_196.
Put the following polynomial file 16661_196.poly in there too.
And then, run "perl factMsieve.pl 16661_196".

16661_196.poly ^*1

n: 22761923482741383587333796810708811974076283280610641113734396995650441795983265548575582887803165472747102807409071465876562790930813684550158653269819754924345596281824867272390312661391
m: 1000000000000000000000000000000000000000
deg: 5
c5: 50
c0: -17
skew: 0.81
type: snfs
lss: 1
rlim: 13300000
alim: 13300000
lpbr: 28
lpba: 28
mfbr: 55
mfba: 55
rlambda: 2.5
alambda: 2.5

*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 22761923482741383587333796810708811974076283280610641113734396995650441795983265548575582887803165472747102807409071465876562790930813684550158653269819754924345596281824867272390312661391 | ecm -n -c 204 5e4

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

echo 22761923482741383587333796810708811974076283280610641113734396995650441795983265548575582887803165472747102807409071465876562790930813684550158653269819754924345596281824867272390312661391 | ecm -n -c 430 25e4

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

echo 22761923482741383587333796810708811974076283280610641113734396995650441795983265548575582887803165472747102807409071465876562790930813684550158653269819754924345596281824867272390312661391 | ecm -n -c 904 1e6

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

echo 22761923482741383587333796810708811974076283280610641113734396995650441795983265548575582887803165472747102807409071465876562790930813684550158653269819754924345596281824867272390312661391 | ecm -n -c 2350 3e6

Submit factors

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