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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.

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