## One for those hunting for covering sets

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• Find an n such that for odd prime p, p^p+n is prime only for one value of p. Phil () ASCII ribbon campaign () Hopeless ribbon campaign / against
Message 1 of 3 , Nov 12, 2006
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Find an n such that for odd prime p, p^p+n is prime only for one value of p.

Phil

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[stolen with permission from Daniel B. Cristofani]

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• ... Even n, that is. Negative odd n values can force all values to be even, such that one of the terms is 2. (As spotted by Ronny off-list - good catch.) Phil
Message 2 of 3 , Nov 12, 2006
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--- Phil Carmody <thefatphil@...> wrote:
> Find an n such that for odd prime p, p^p+n is prime only for one value of p.

Even n, that is. Negative odd n values can force all values to be even, such
that one of the terms is 2. (As spotted by Ronny off-list - good catch.)

Phil

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/\ against HTML mail /\ against gratuitous bloodshed

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• ... I never heard an answer for this, but I think it is: -25 Or, actually, 2-p^p for p any odd prime. Tom Hadley [Non-text portions of this message have been
Message 3 of 3 , Nov 20, 2006
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Phil wrote on 11/12/2006 04:10:28 AM:

> Find an n such that for odd prime p, p^p+n is prime only
> for one value of p.
>
> Phil
>

I never heard an answer for this, but I think it is: -25
Or, actually, 2-p^p for p any odd prime.