# Re: Interesting Article

Judy Ann Brown (judyann@dimacs.rutgers.edu)
Fri, 27 Jun 1997 22:04:43 -0400

Hi Nancy

Now on to Sagan's book. I don't think I've read it, but you are correct in your
statements. Th only even prime is 2. No other even number is prime because all
have 2 as a 3rd factor. One is not prime. I've read several definitions for
prime. Some start with "A prime is any integer GREATER THAN ONE that has..."
Others state more simply that "A prime number has EXACTLY TWO positive integral
factors" this eliminates 1 because it has only 1 factor.

There are several sites on the web where you can find lists of prime numbers.
You could also search the archives of Dr. Math at the Math Forum at Swarthmore
for more prime info.

Judy

Responding to the message of <33B42E1F.4BF9@TENET.EDU>
from "Nancy Shields" <nshields@tenet.edu>:
>
> Hi! The Texas Education Network (TENET) has *finally* upgraded itself
> so that teachers can get graphics, Netscape, etc. on the computers at
> home. I am writing you all for the first time on Netscape. I just
> clicked on the link Pat had in his email on autism and went to the
> WAshington Post article, pictures and all. This is exciting! I just
> had to communicate with all of you at dimacs my excitement. Now to find
> time to visit the puzzle of the week and all of the neat web sites you
> all have shown!
>
> On another note. With the movie Contact, based on the book by Sagan,
> coming out in July, I decided I wanted to read the book. Now that I am
> about a third of the way through it, I think I read it once, it seems
> familiar. My question is, the message from space is sent via series of
> prime numbers. In the book, on page 86, he states, "No even number is
> prime." Later on the same page he says "just the first few hundred
> prime numbers in order, a cycling back to the beginning and again the
> simple binary arithmetic representations: 1, 2, 3, 5, 7, 11, 13, 17,
> 19, 23, 29, 31 . . ." I think (but with Carl Sagan evidently stating
> something else, I feel unsure) that 2 (an even number (is prime), and
> that in the long list of primes, that he should not have listed 1--which
> is neither prime nor composite. Have any of you read this book, and if
> so, what do you think about these statements? (The book is pretty good,
> by the way, if you haven't read it. I hope the movie isn't totally
> different, as in the case of The Lost World!)
>
> Signing off from Netscape (YAY)
> Nancy Shields
> Beeville, Texas '96
>
> .

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Judy Ann Brown
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