Contribution and Reservation

8·10²²⁰-1 =: 7(9)₂₂₀_<221>; = 1727611904440464642211967_<25> · [46306696425497388519340233472175987643115126030864710153839105852949247389361465845828864013338600142081055865034011444916102327659963822677709376922776578825970007360660185240970105097148810477697_<197>] SUBMIT/RESERVE

Status

Expression:	8·10²²⁰-1
Composite Factor:	463066964254973885193402334721759876431151260308647101538391 058529492473893614658458288640133386001420810558650340114449 161023276599638226777093769227765788259700073606601852409701 05097148810477697 (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 222.30-digit and the GNFS difficulty is 196.67-digit. SNFS must be faster than GNFS. It will take about 107 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 79999_220.
Put the following polynomial file 79999_220.poly in there too.
And then, run "perl factMsieve.pl 79999_220".

79999_220.poly ^*1

n: 46306696425497388519340233472175987643115126030864710153839105852949247389361465845828864013338600142081055865034011444916102327659963822677709376922776578825970007360660185240970105097148810477697
m: 10000000000000000000000000000000000000
deg: 6
c6: 2
c0: -25
skew: 1.52
type: snfs
lss: 1
rlim: 35000000
alim: 35000000
lpbr: 29
lpba: 29
mfbr: 58
mfba: 58
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 30-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
30	25e4	430	Makoto Kamada	Jul 24, 2008
30	25e4	430 / 430
35	1e6	0 / 825
35	1e6	/ 825
40	3e6	0 / 2336 (294)
40	3e6	/ 2336 (294)
45	11e6	0 / 4479 (677)
45	11e6	/ 4479 (677)
50	43e6	0 / 7553 (1277)
50	43e6	/ 7553 (1277)

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

echo 46306696425497388519340233472175987643115126030864710153839105852949247389361465845828864013338600142081055865034011444916102327659963822677709376922776578825970007360660185240970105097148810477697 | ecm -n -c 825 1e6

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

echo 46306696425497388519340233472175987643115126030864710153839105852949247389361465845828864013338600142081055865034011444916102327659963822677709376922776578825970007360660185240970105097148810477697 | ecm -n -c 2336 3e6

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

echo 46306696425497388519340233472175987643115126030864710153839105852949247389361465845828864013338600142081055865034011444916102327659963822677709376922776578825970007360660185240970105097148810477697 | ecm -n -c 4479 11e6

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

echo 46306696425497388519340233472175987643115126030864710153839105852949247389361465845828864013338600142081055865034011444916102327659963822677709376922776578825970007360660185240970105097148810477697 | ecm -n -c 7553 43e6

Submit factors

Make reservation

Back to Factorizations of near-repdigit numbers