15704Re: [PrimeNumbers] another way to calculate primes
- Dec 6, 2004I noticed I forgot to include 3, it was only distraction.
However I think this statement is enaugh:
the set of prime numbers = 2, 3, 5 PLUS all odd numbers > 5, not ending by 5 and not composite.
7 is included: 7>5, 7 is odd not ending by 5 AND not composite.
9 is not included: 9 is composite (3^2)
11 is included: 11>5, 11 is odd not ending by 5 AND not composite.
By "composite number" I meant an integer that is the product of two or more integers. I hope I used
the right translation of what I meant.
Of course we can use a more concise statement:
pimes = all not composite numbers > 1.
We will find that, with the exception of 2 and 5, all prime numbers have as final digit one of
these: 1, 3, 7, 9.
----- Original Message -----
From: "Mary & Graeme" <candlesque@...>
To: "Mazzarello Gianni" <g.mazzarello@...>
Sent: Tuesday, December 07, 2004 12:32 AM
Subject: Re: [PrimeNumbers] another way to calculate primes
> May I make an observation here?
>> the set of prime numbers = 2, 5 PLUS all odd numbers > 5, not ending by
>> 5 and not composite.
> Might it not be more correct to state:
> the set of prime numbers = 2,3,5,7,11 PLUS all odd numbers > 5, not ending by
> 5 and not composite.
> ... since the first statement would seem to allow 9 as a prime, and omits 3?
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