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2020-10-10, 16:23   #1695
James Heinrich

"James Heinrich"
May 2004
ex-Northern Ontario

62028 Posts

Quote:
 Originally Posted by storm5510 I am not sure how anyone would convert this to a single large number. Consider it a curiosity, amusement, or whatever.
PARI/GP, enter print( ((((2^943-1)/41884514890068404473)/21698431)/62209711)/164511353 );
and you get your 241 digits:
Code:
7993740247389956264853174304168322255931238346246097321873539588852601041591321387921101681164706423023658390690691167622105779566348116865818161116278520751265794272168974387055181655888422451232542011347384356257680009348025432182336941183
And if you decide to factor that C241 with YAFU, you get:
Code:
***factors found***

P18 = 138325941036565103
P29 = 57644473457648767005697802783
P25 = 9280993516297855054039457
P171 = 108017532617736915133406584684682016398182243100347598313436462729073911856247557922662614974708675029796424611721425364738654561651249349759454300640753645387500306111631

Last fiddled with by James Heinrich on 2020-10-10 at 16:25

2020-10-10, 17:03   #1696
storm5510
Random Account

Aug 2009
U.S.A.

32408 Posts

Quote:
 Originally Posted by James Heinrich PARI/GP, enter print( ((((2^943-1)/41884514890068404473)/21698431)/62209711)/164511353 ); and you get your 241 digits: Code: 7993740247389956264853174304168322255931238346246097321873539588852601041591321387921101681164706423023658390690691167622105779566348116865818161116278520751265794272168974387055181655888422451232542011347384356257680009348025432182336941183 And if you decide to factor that C241 with YAFU, you get: Code: ***factors found*** P18 = 138325941036565103 P29 = 57644473457648767005697802783 P25 = 9280993516297855054039457 P171 = 108017532617736915133406584684682016398182243100347598313436462729073911856247557922662614974708675029796424611721425364738654561651249349759454300640753645387500306111631
Yes, this is a composite. The largest single factor I found has 53 digits:

Quote:
 20681466401231162257298375941479424220537996009370817
It only took a few seconds to run, but produced a 3,000+ line output file which I captured. It is attached below if anyone wants to look...
Attached Files
 gmp-943.zip (24.1 KB, 25 views)

2020-10-10, 22:39   #1697
James Heinrich

"James Heinrich"
May 2004
ex-Northern Ontario

2·1,601 Posts

Quote:
 Originally Posted by LaurV there are some misconcordances between this table and this table. We have all their lines, but sometimes with different names (usually, anonymous, when the right names should be provided, even if they are not members of gimps, that would be fair for the discoverers), while they do NOT have all our lines, probably some of our records were not reported to them (like Ryan's M2671 factor). Somebody may report our records to them, so they become part of the "all times/all kinds" record history (not me, the discoverer should do it, but if they are not interested, maybe James?).
I have sent Paul an email offering him some automated new-factor notification if he's interested.

@LaurV: since you brought it up, would you care to compile a list of the factors for which discover names are known but my site shows anonymous, please? Thanks!

 2020-10-11, 07:49 #1698 LaurV Romulan Interpreter     Jun 2011 Thailand 8,963 Posts If I can't keep my mouth shut... hihi. Edit: Ok, I will look into it. Edit 2: At first sight, [J. Bos/T. Kleinjung/A. Lenstra/P. Montgomery]'s factors, they factored many low mersennes by ECM and SNFS, but because none of them is member of Gimps, such factors were added to PrimeNet's DB like "anonymous". Or, in George's name (probably, he added the factor to the DB, there is no intention in "stealing" their factors) - the case for M1237. Last fiddled with by LaurV on 2020-10-11 at 08:11
 2020-10-12, 09:48 #1699 Viliam Furik   Jul 2018 Martin, Slovakia 22·67 Posts Almost top 3 M10017487 has a 162.539-bit (49-digit) composite (P23+P27) factor: 8492545109166755533258311668299806208565163467423 (P-1,B1=5000000,B2=150000000) When I found this beauty in results.txt, I said: "Well, that will be composite...". It was...
2020-10-12, 17:09   #1700
storm5510
Random Account

Aug 2009
U.S.A.

32408 Posts

Quote:
 Originally Posted by Viliam Furik M10017487 has a 162.539-bit (49-digit) composite (P23+P27) factor: 8492545109166755533258311668299806208565163467423 (P-1,B1=5000000,B2=150000000) When I found this beauty in results.txt, I said: "Well, that will be composite...". It was...
I understand what a composite is. Would somebody like to elaborate on the "Pxx" references?

2020-10-12, 17:13   #1701
masser

Jul 2003

22×7×53 Posts

Quote:
 Originally Posted by storm5510 I understand what a composite is. Would somebody like to elaborate on the "Pxx" references?
The composite factored into a 23 digit prime and a 27 digit prime.

2020-10-12, 19:43   #1702
James Heinrich

"James Heinrich"
May 2004
ex-Northern Ontario

2·1,601 Posts

Quote:
 Originally Posted by LaurV At first sight, [J. Bos/T. Kleinjung/A. Lenstra/P. Montgomery]'s factors, they factored many low mersennes by ECM and SNFS, but because none of them is member of Gimps, such factors were added to PrimeNet's DB like "anonymous". Or, in George's name (probably, he added the factor to the DB, there is no intention in "stealing" their factors) - the case for M1237.
I have adjusted 3 factors to "Joppe Bos, Thorsten Kleinjung, Arjen Lenstra, Peter Montgomery", two were "anonymous", one was George.

There is an odd 4th case: M1471 which Zimmermann credits to Ryan Propper on 2017-Aug-31 but GIMPS data has kkmrkkblmbrbk reporting it on 2017-09-03. It's possible that it was discovered outside GIMPS and reported (but not actually discovered) by kkmrkkblmbrbk a few days later (edit: this seems to support that), since I don't think Ryan Propper joined GIMPS until around 2019-Apr (at least that's when factors with his name on them start appearing).
So, should I change the credit for M1471 to Ryan?

2020-10-12, 21:09   #1703
ryanp

Jun 2012
Boulder, CO

21310 Posts

Quote:
 Originally Posted by James Heinrich There is an odd 4th case: M1471 which Zimmermann credits to Ryan Propper on 2017-Aug-31 but GIMPS data has kkmrkkblmbrbk reporting it on 2017-09-03. It's possible that it was discovered outside GIMPS and reported (but not actually discovered) by kkmrkkblmbrbk a few days later
Yep, that was me:

Code:
GMP-ECM 6.4.4 [configured with GMP 6.0.0, --enable-asm-redc] [ECM]
Input number is
414112359191997701534253596492500106450300358197797860629666662626749053242608219494442402695651576837870340296832489287087736334825594271746068631644666774347474623919652707232075336460653035066984955186871523283455060667679907961096868238556949992989771660891724444656348335990462979243681517917537081864618887895837966964799536787373376827405632123493586648835674823827101723072520023440275366679460254103690151
(414 digits)
Using special division for factor of 2^1471-1
Using B1=850000000, B2=15892628251516, polynomial Dickson(30),
sigma=1149118327
dF=524288, k=5, d=5705700, d2=17, i0=132
Expected number of curves to find a factor of n digits:
35      40      45      50      55      60      65      70      75      80
15      47      168     661     2867    13623   69471   381778  2221086 1.4e+07
Step 1 took 10424603ms
Using 47 small primes for NTT
Estimated memory usage: 4389M
Initializing tables of differences for F took 13531ms
Computing roots of F took 265269ms
Building F from its roots took 107976ms
Computing 1/F took 43111ms
Initializing table of differences for G took 3177ms
Computing roots of G took 275418ms
Building G from its roots took 114795ms
Computing roots of G took 296465ms
Building G from its roots took 121469ms
Computing G * H took 20867ms
Reducing  G * H mod F took 22248ms
Computing roots of G took 303952ms
Building G from its roots took 134736ms
Computing G * H took 21110ms
Reducing  G * H mod F took 23203ms
Computing roots of G took 291818ms
Building G from its roots took 117351ms
Computing G * H took 20115ms
Reducing  G * H mod F took 22810ms
Computing roots of G took 305851ms
Building G from its roots took 124813ms
Computing G * H took 19687ms
Reducing  G * H mod F took 20117ms
Computing polyeval(F,G) took 207279ms
Computing product of all F(g_i) took 1019ms
Step 2 took 2901560ms
********** Factor found in step 2: 61491618977549042678155153540458255504752992030160252118535699943713
Found probable prime factor of 68 digits: 61491618977549042678155153540458255504752992030160252118535699943713
Probable prime cofactor 6734452045297304612995050904133968305694025489494814555211753778337449397088976789153790263210262363727443589087252640846370390818555151954319223922183531363828896443099275063889485014446803977469139684639880343219143574884603136545584618534007354180853969730250054739420717651286559832852943449096627017735640776807663419415624956377103688592327 has 346 digits

2020-10-12, 22:11   #1704
James Heinrich

"James Heinrich"
May 2004
ex-Northern Ontario

C8216 Posts

Quote:
 Originally Posted by ryanp Yep, that was me
Thanks Ryan for the confirmation. I have adjusted the discovery credit/date and added B1/B2/Sigma details to the record.
If there are any factors of your discovery that are improperly credited (e.g. anonymous results presumably pre-dating your involvement with GIMPS) please let me know and I can adjust accordingly.

2020-10-13, 03:44   #1705
LaurV
Romulan Interpreter

Jun 2011
Thailand

8,963 Posts

Quote:
 Originally Posted by James Heinrich but GIMPS data has kkmrkkblmbrbk reporting it on 2017-09-03.
That's GP2 on the forum, and he posted public some time ago about adding this factor from Ryan to DB by himself. No foul play.

Last fiddled with by LaurV on 2020-10-13 at 03:48

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