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Old 2019-05-23, 13:19   #474
unconnected
 
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Nice ECM-hit on biggest "wanted" number in the Near-repdigit factorization project https://stdkmd.net/nrr/

Actual number is (115×10300-1)/3

Code:
GMP-ECM 7.0.4 [configured with GMP 6.1.2, --enable-asm-redc] [ECM]
Input number is 38333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333 (302 digits)
<...>
Using B1=43000000, B2=240490660426, polynomial Dickson(12), sigma=1:844078124
Step 1 took 191607ms
Step 2 took 53755ms
********** Factor found in step 2: 720066876637422731167474238991440469254132874911585521
Found prime factor of 54 digits: 720066876637422731167474238991440469254132874911585521
Prime cofactor 53235795975427741890465391698230860095695557182785047144812320174995249922788196716408458115340398138332035237794082407962820659895888598957826697840104976519782742746845880877947232301184372592292646847839607171094957249880926769591748873037854373 has 248 digits
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Old 2019-07-08, 22:41   #475
Stargate38
 
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Nice split for the C119 from (739172^23+1)/739173:

Code:
***factors found***

P60 = 218098651003220797209013762101015980204333755427573114530643
P60 = 359383030057111324963136898955035440937919265836837473422953

ans = 1
FactorDB link

If not for the special form, it could've been used as a small RSA number, although it would be cracked in at most a few hours.

Last fiddled with by Stargate38 on 2019-07-08 at 22:47 Reason: too many parentheses
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Old 2019-07-24, 07:37   #476
fivemack
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Default L2253 C193 cofactor

Code:
Sat Jun 22 22:52:08 2019  found 221473851 hash collisions in 819883728 relations
Sat Jun 22 22:52:44 2019  added 121330 free relations
Sat Jun 22 22:52:44 2019  commencing duplicate removal, pass 2
Sat Jun 22 23:12:50 2019  found 206676643 duplicates and 613328415 unique relations
...
Wed Jun 26 21:04:34 2019  weight of 47629874 cycles is about 5430355964 (114.01/cycle)
...
Thu Jun 27 16:51:05 2019  matrix is 47628697 x 47629115 (20052.6 MB) with weight 4768300540 (100.11/col)
Thu Jun 27 16:51:05 2019  sparse part has weight 4494589987 (94.37/col)
Thu Jun 27 16:51:05 2019  using block size 8192 and superblock size 473088 for processor cache size 19712 kB
Thu Jun 27 16:53:10 2019  commencing Lanczos iteration (14 threads)
Thu Jun 27 16:53:10 2019  memory use: 28219.8 MB
...
Wed Jul 24 00:45:37 2019  lanczos halted after 186610 iterations (dim = 47628697)
Wed Jul 24 00:48:30 2019  recovered 33 nontrivial dependencies
...
Wed Jul 24 04:31:32 2019  p76 factor: 1080849092176697583140039262728062078480677411725582885800141395685329563131
Wed Jul 24 04:31:32 2019  p118 factor: 2487242330858102170748016130425558018779040628976630249454570502152985898147406216550102375171246590101484455922197359
Linear algebra on 14 cores i9/7940X, 256-bit vectors.

Sieving between April 1 and June 22; 734813293 thread-seconds across a number of machines. Sieved 76..400 with 15e (started in the middle and then sieved on either side as the yields went down, so that's the narrowest region that would get enough relations) with

Code:
n: 2688333615331433020642446747149440986283678638176205541641754312932820814295074220965678187428410875031545875881257723735692836520162515677425285432734833508071695321927492427322546769031971029
# norm 6.748829e-19 alpha -7.525095 e 1.198e-14 rroots 3
skew: 368024608.71
c0: 123272612786479316312350884349842837614862419023
c1: -8888039873820606651882838453601725169289
c2: -6398405309760975776966814915379
c3: -74102914865935467793635
c4: -344134329264960
c5: 556920
Y0: -21713911810858617860786743761277388982
Y1: 11185023447043546081
lpbr: 33
lpba: 33
mfbr: 66
mfba: 96
alambda: 3.5
rlambda: 2.3
alim: 400000000
rlim: 400000000
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Last fiddled with by fivemack on 2019-07-24 at 07:39
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Old 2019-09-07, 11:52   #477
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I'm doing SNFS on L1475 (16e siever); should be done by Christmas

Last fiddled with by fivemack on 2019-09-07 at 11:52
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Old 2019-10-29, 19:21   #478
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I've never previously found any 60-digit (or larger) factor with ECM:
Code:
Run 101 out of 3000:
Using B1=650000000, B2=9535639713616, polynomial Dickson(30), sigma=1:3818487872
Step 1 took 4152883ms
Step 2 took 755742ms
********** Factor found in step 2: 114459642089212545052889653702355609483801498441054247062970513039199
Found prime factor of 69 digits: 114459642089212545052889653702355609483801498441054247062970513039199
Composite cofactor 547759313290813250992293689285028656088755821050302239716096889612754975332977050832026673133846517426854720087620431222701 has 123 digits
The input was the C191 cofactor of 13*2^904-1.

Last fiddled with by VBCurtis on 2019-10-29 at 21:23
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Old 2019-10-29, 20:17   #479
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Don't you mean 69 digit factor???

That is the 2nd longest found this year by ECM.

https://members.loria.fr/PZimmermann...ds/ecmnet.html
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Old 2019-10-29, 21:03   #480
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Nice hit!
I won’t be surprised if this p69 will be the largest cofactor.
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Old 2019-10-29, 21:23   #481
VBCurtis
 
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Quote:
Originally Posted by PhilF View Post
Don't you mean 69 digit factor???

That is the 2nd longest found this year by ECM.

https://members.loria.fr/PZimmermann...ds/ecmnet.html
I meant any factor 60 digits or larger. I'll edit the post.
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Old 2019-10-29, 23:02   #482
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Quote:
Originally Posted by unconnected View Post
Nice hit!
I won’t be surprised if this p69 will be the largest cofactor.
Correct- a pair of p62s:
Code:
46356311197359827190178181682835030591140486033322886383700443 
11816283460492651997250239639885639004584054186894361593917207
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Old 2019-11-17, 04:03   #483
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2^1429+1 has a 47-digit factor: 11485943839018053479863036296614076404887447123
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Old 2019-12-12, 02:57   #484
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Found my largest TF factor in an exciting way

490609746862823011746041<24> divides M726064763[1]
78 bits! A rough k that wasn't likely to fall to P-1.
Took ~50 GHz days (~2 hr on 1080)

This is only the 7th number with 10 known factors (and the 2nd below 1B)[2]

Maybe ATH will TF to 80 bits.

[1] https://www.mersenne.ca/exponent/726064763
[2] https://www.mersenne.ca/manyfactors....&o=d&fac_min=7

Last fiddled with by SethTro on 2019-12-12 at 03:08
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