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Re: prime numbers and African artifact
Timothy D. Shoppa (shoppa@almach.caltech.edu)
14 Jul 1995 15:24 PST
In article <3u6c7k$s9t@infohub.engr.sgi.com>, erikw@bat.engr.sgi.com (Erik Wahlstrom) writes...
>
>In article <3u5act$j2u@zen.hursley.ibm.com>, martin@melon.wdg.uk.ibm.com writes:
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>> Hang on, I think I can finally wrap this up.
>>
>> (a) 254365465431652436514232 is not divisible by 2 (see above).
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> FALSE!
>
>>
>> (b) Since the first number is neither a 5 nor a 0, the number is
>> not divisible by 5.
>>
>> (c) By repeatedly adding the digits together as above, we get the number 10.
>> Now any number which doesn't divide into 10 clearly doesn't divide into
>> the whole number. 10 is divisible only by 5 and 2, which we have already
>> shown don't divide the number.
>>
>> So 254365465431652436514232 is most definitely prime, not to mention square
>> (yes, a member of the small set of square primes) and also a Fibonacci number.
>
>
>254365465431652436514232 IS NOT A PRIME. It's an Even number, End of story.
>Remember the only even PRIME number is 2.
>
>Cheers Erik
I just have to take pride in this one. It was more than a week ago that
I suggested that 9, 15, and 21 were very useful prime numbers and started
this whole troll. (Actually, I never intended it to be a troll. I even
put a smiley after my original suggestion. But it's nevertheless suckered
several in!) The above, I think, is the finest catch. It's going
to be stuffed and mounted above the fireplace.
Tim. (shoppa@altair.krl.caltech.edu)
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