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if p is prime, then so is (2^p - 1)

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henh...@gmail.com

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Aug 13, 2022, 2:08:55 PM8/13/22
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(no need to "wait a few days, before..." ------ this must've be known for Centuries)


Are the following both true ?

A. if p is prime, then so is (2^p - 1)

---------- for what kind of P does this fail ?


B. if (2^p - 1) is prime, then so is p.




( 2018年2月現在、50個のメルセンヌ素数が発見されている。 )

Kerr-Mudd, John

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Aug 13, 2022, 2:28:53 PM8/13/22
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On Sat, 13 Aug 2022 11:08:53 -0700 (PDT)
"henh...@gmail.com" <henh...@gmail.com> wrote:

> (no need to "wait a few days, before..." ------ this must've be known for Centuries)
>
>
> Are the following both true ?
>
> A. if p is prime, then so is (2^p - 1)
>
> ---------- for what kind of P does this fail ?
>
>
> B. if (2^p - 1) is prime, then so is p.
>
>
It's quite a Little Puzzle

https://en.wikipedia.org/wiki/Fermat%27s_little_theorem



Please try harder.

--
Bah, and indeed Humbug.

Eric Sosman

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Aug 13, 2022, 3:45:02 PM8/13/22
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... or at least let it marin-ate a bit longer.

--
eso...@comcast-dot-net.invalid
Look on my code, ye Hackers, and guffaw!
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