Re: Prime Puzzle with Mathematica [CORRECTION]

• To: mathgroup at smc.vnet.net
• Subject: [mg92712] Re: [mg92680] Prime Puzzle with Mathematica [CORRECTION]
• From: Bob Hanlon <hanlonr at cox.net>
• Date: Sat, 11 Oct 2008 06:43:59 -0400 (EDT)

```This can be written more compactly as

Select[Subsets[p, {3}], And @@ PrimeQ /@ Mean /@ Subsets[#, {2, 3}] &]

Bob Hanlon

---- Bob Hanlon <hanlonr at cox.net> wrote:

=============
p = Table[Prime[i], {i, 5, 25}]

{11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97}

Select[Subsets[p, {3}],
And @@ (PrimeQ /@ (Mean /@ Drop[Subsets[#], 4])) &]

{{11, 47, 71}}

Bob Hanlon

---- amzoti <amzoti at gmail.com> wrote:

=============
Hi All,

trying to find an efficient way to this in Mathematica.

I found the answer - but it was a manual list manipulation - and it
was ugly!

Any suggestions?

3 Nice Primes:

Find three 2-digit prime numbers such that:

* The average of any two of the three is a prime number, and
* The average of all three is also a prime number

Thanks!

~A

--

Bob Hanlon

--

Bob Hanlon

```

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