Contribution and Reservation

4·10²⁰⁸+9 =: 4(0)₂₀₇9_<209>; = 56041 · 1840599613_<10> · [387788377581688289371431249461030381022462384738758093566030054271723711277607755787221028097718270404721169014157843013308491791342913847779739566394836804064339457446263608159998580483142197173_<195>] SUBMIT/RESERVE

Status

Expression:	4·10²⁰⁸+9
Composite Factor:	387788377581688289371431249461030381022462384738758093566030 054271723711277607755787221028097718270404721169014157843013 308491791342913847779739566394836804064339457446263608159998 580483142197173 (195-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 208.60-digit and the GNFS difficulty is 194.59-digit. SNFS must be faster than GNFS. It will take about 37 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 40009_208.
Put the following polynomial file 40009_208.poly in there too.
And then, run "perl factMsieve.pl 40009_208".

40009_208.poly ^*1

n: 387788377581688289371431249461030381022462384738758093566030054271723711277607755787221028097718270404721169014157843013308491791342913847779739566394836804064339457446263608159998580483142197173
m: 200000000000000000000000000000000000000000
deg: 5
c5: 125
c0: 9
skew: 0.59
type: snfs
lss: 1
rlim: 21000000
alim: 21000000
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 195-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	0 / 0
35	1e6	118	Makoto Kamada	Mar 2, 2009
		118 / 904
		/ 786
40	3e6	0 / 2318 (280)
40	3e6	/ 2318 (280)
45	11e6	0 / 4475 (672)
45	11e6	/ 4475 (672)
50	43e6	0 / 7553 (1276)
50	43e6	/ 7553 (1276)

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

echo 387788377581688289371431249461030381022462384738758093566030054271723711277607755787221028097718270404721169014157843013308491791342913847779739566394836804064339457446263608159998580483142197173 | ecm -n -c 786 1e6

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

echo 387788377581688289371431249461030381022462384738758093566030054271723711277607755787221028097718270404721169014157843013308491791342913847779739566394836804064339457446263608159998580483142197173 | ecm -n -c 2318 3e6

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

echo 387788377581688289371431249461030381022462384738758093566030054271723711277607755787221028097718270404721169014157843013308491791342913847779739566394836804064339457446263608159998580483142197173 | ecm -n -c 4475 11e6

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

echo 387788377581688289371431249461030381022462384738758093566030054271723711277607755787221028097718270404721169014157843013308491791342913847779739566394836804064339457446263608159998580483142197173 | ecm -n -c 7553 43e6

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