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-   enzocreti (https://www.mersenneforum.org/forumdisplay.php?f=156)

 enzocreti 2020-08-31 11:27

probable dud

((2^1875230-1)*10^564501+2^1875229-1) has small factors?

I don't know...:smile:

 mathwiz 2020-08-31 13:47

Well, have you PRP tested this with PFGW? Or are you asking us to do it for you?

 retina 2020-08-31 13:50

[QUOTE=mathwiz;555531]Or are you asking us to do it for you?[/QUOTE]It wouldn't be much different from Google demanding everyone do their job for them with the captcha images.

 enzocreti 2020-08-31 13:52

[QUOTE=mathwiz;555531]Well, have you PRP tested this with PFGW? Or are you asking us to do it for you?[/QUOTE]

Unfortunally my computer is broken!

 CRGreathouse 2020-08-31 15:08

So what makes you think it is a probable prime? :confused:

 storm5510 2020-08-31 15:34

[QUOTE=enzocreti;555513][B]((2^1875230-1)*10^564501+2^1875229-1) [/B]has small factors?[/QUOTE]

This appears to be a request for somebody with a lot of cores to run it. I am not sure [I]PFGW[/I] could handle it in this form. Then again, maybe it could. Any person trying may need several generations of descendants to see it done. It might have to look something like this though:

[QUOTE](((2^1875230-1)*10^564501+2)^1875229-1)[/QUOTE]I am not sure how [I]PFGW[/I] handles parenthetical's or if it will accept them at all. :no:

 enzocreti 2020-08-31 15:43

[QUOTE=CRGreathouse;555541]So what makes you think it is a probable prime? :confused:[/QUOTE]

Pg(69660) is prime

69660 is multiple of 215 and congruent to 215 mod 323...it is also 6 mod 13... using wolphram numbers of this form are 69660+xn where x i don't remember what it is.

69660 is the least number N such that N is 215 mod 323, N is 0 mod 215 and N is 6 mod 13...
then you have other values using Chinese remainder theorem

 Uncwilly 2020-08-31 15:43

:poke:
:dnftt:

 mathwiz 2020-08-31 15:52

[QUOTE=enzocreti;555533]Unfortunally my computer is broken![/QUOTE]

so how/where did you somehow come up with this number?

 CRGreathouse 2020-08-31 17:36

[QUOTE=enzocreti;555550]Pg(69660) is prime

69660 is multiple of 215 and congruent to 215 mod 323...it is also 6 mod 13... using wolphram numbers of this form are 69660+xn where x i don't remember what it is.

69660 is the least number N such that N is 215 mod 323, N is 0 mod 215 and N is 6 mod 13...
then you have other values using Chinese remainder theorem[/QUOTE]

I agree that 69660 == chinese([Mod(215,323), Mod(0,215), Mod(6,13)]), and I'm prepared to assume that Pg(69660) is prime. But why should that make us think that

((2^1875230-1)*10^564501+2^1875229-1)

is likely to be prime?

 mathwiz 2020-08-31 17:59

[QUOTE=CRGreathouse;555541]So what makes you think it is a probable prime? :confused:[/QUOTE]

Putting this to rest:

[CODE]\$ ./pfgw64 -i -V -N -T8 -q"((2^1875230-1)*10^564501+2^1875229-1)"
PFGW Version 4.0.0.64BIT.20190528.x86_Dev [GWNUM 29.8]

Generic modular reduction using generic reduction AVX-512 FFT length 384K, Pass1=1K, Pass2=384, clm=1, 8 threads on A 3750464-bit number
Resuming at bit 1480000
((2^1875230-1)*1....501+2^1875229-1) is composite: RES64: [52E573162A497910] (5201.6106s+0.0149s)[/CODE]

As to whether the factors are small, I have neither the time nor interest to care.

 Batalov 2020-08-31 18:03

... ... Easily sniped.

 VBCurtis 2020-08-31 18:14

[QUOTE=mathwiz;555571]Putting this to rest:

[CODE]\$ ./pfgw64 -i -V -N -T8 -q"((2^1875230-1)*10^564501+2^1875229-1)"
[/QUOTE]

The problem with doing this is that it achieves the opposite of your hope- rather than show the OP that his ideas are bunk and shouldn't be written out in public, it teaches him that if he asks a dumb enough question, someone will do the calculation work for him to show it's dumb. What he wants is someone to do the computing, and you did his bidding.

We prefer you didn't.

It's cool to post the command you would use (as you also did), so that OP could do it himself if he wasn't so lazy.

 Batalov 2020-08-31 18:15

[COLOR="Red"]MOD NOTE: next cry of "Fire!" in a cinema theater will be punished by a detention.[/COLOR]

People do come to this forum to find news of a, say, next Mersenne prime (which are now pre-screened as PRPs), so the next person who will call their thread "[I]Probable prime[/I]" and when asked for reasons why that did such a thing would show a patty cake made out of #2, will get that cake on their face and a two week banishment as well. Call it something else, like "I made up a number", or "asking for an advice" or "I don't know how to check this", or whatever.

 enzocreti 2020-09-01 07:21

...but this is almost surely PRP!

(2^3680800-1)*10^1108031+2^3680799-1

 enzocreti 2020-09-01 07:32

...not that's not prp

(2^1430136-1)*10^430514+2^1430135-1???

the candidates have the form

pg(69660+1360476n)

because 69660 is the least N congruent to 215 mod 323 and 0 mod 324 and 6 mod 13

 Batalov 2020-09-01 07:48

[QUOTE=enzocreti;555614] ...but this is almost surely PRP!
(2^3680800-1)*10^1108031+2^3680799-1[/QUOTE]
Divisible by 71.

(2^1430136-1)*10^430514+2^1430135-1[/QUOTE]
Divisible by 14437.

[/QUOTE]
Correct.

How about a 2 weeks ban?

 paulunderwood 2020-09-01 07:51

[QUOTE=Batalov;555616]Divisible by 71.

Divisible by 14437.

Correct.

How about a 2 weeks ban?[/QUOTE]

You beat me to it! :jail:

 enzocreti 2020-09-01 07:53

...i did not...

i did not take into account that N must be 10^m mod 41

let's guess congruent to 1 mod 41

so the candidates must have the form

pg(69660+11992595940n)

impossible to test!

 Batalov 2020-09-01 08:02

[QUOTE=enzocreti;555619]i did not take into account that N must be 10^m mod 41

let's guess congruent to 1 mod 41[/QUOTE]
Do. Not. Guess.
There are no guesses in math.
log[SUB]10[/SUB]2 is irrational and just [I]happens to be[/I] locally close to 0.3 and that is the only reason that there is some local periodicity of modulos w.r.t. n.
This periodicity doesn't hold for larger values of n, so simply stop posting guesses pulled out of your ear [SPOILER](or, as some less polite folks would say, rear)[/SPOILER].

 storm5510 2020-09-01 16:55

[QUOTE=mathwiz;555571]Putting this to rest:

[CODE]\$ ./pfgw64 -i -V -N -T8 -q"((2^1875230-1)*10^564501+2^1875229-1)"
PFGW Version 4.0.0.64BIT.20190528.x86_Dev [GWNUM 29.8]

Generic modular reduction using generic reduction AVX-512 FFT length 384K, Pass1=1K, Pass2=384, clm=1, 8 threads on A 3750464-bit number
Resuming at bit 1480000
((2^1875230-1)*1....501+2^1875229-1) is composite: RES64: [52E573162A497910] (5201.6106s+0.0149s)[/CODE]As to whether the factors are small, I have neither the time nor interest to care.[/QUOTE]

I have very little interest. These appear to be something simply pulled out of the air. I tried several formats with PFGW. None worked. I did not try the one above. I do not see the point of doing so. End of line...

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