Math Is Fun Forum

n872yt3r

Member

Registered: 2013-01-21

Posts: 392

The Sieve of Eratosthenes.

Here's the Sieve of Eratosthenes, the strategy of an ancient Greek mathematician to find prime numbers.
So, x=2, the first prime number. Write a list of numbers from x to y.
Cross out x's multiples, then do the same for the next uncrossed number. The ones crossed out are the composites, and the ones left are the primes, because primes have no factors other than 1 and itself, and composites have at least one more. so if y = 10, then the primes are:
2, 3, 5 and 7,
and the composites are:
4, 6, 8, 9, and 10.

Last edited by n872yt3r (2013-01-25 23:27:30)

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- n872yt3r
Math Is Fun Rocks!
By the power of the exponent, I square and cube you!

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: The Sieve of Eratosthenes.

I do not agree with the last sentence...

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n872yt3r

Member

Registered: 2013-01-21

Posts: 392

Re: The Sieve of Eratosthenes.

Well...... sometimes it works, your right I did not try it enough. I think i'll erase that...

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- n872yt3r
Math Is Fun Rocks!
By the power of the exponent, I square and cube you!