# November 12th, 2005 - Balinares — LiveJournal

## Nov. 12th, 2005

### 04:27 pm - *Food For Thought.*

(Aside: yeah, I've been cranky and unapproachable all week. Yeah, for good reason. Serenity is a perpetual conquest. Sometimes too much is too much, and it takes a few days to find your center again. That's all I'll say about that.)

It occurred to me just a moment ago that while some mathematical riddles required a certain amount of background (in particular, I was trying to remember if proving there are infinitely many prime numbers is one of those), some don't, and thus make a good brainteaser for the non-mathematician.

Here's a good one. Comments are screened. Impress me!

*p*be a prime number other than

*2*.

Prove that

*(p-1).p.(p+1)*must be a multiple of

*24*.

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