Difference between revisions of "Prime number"
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− | A '''prime number''' (or simply '''prime''') is a | + | A '''prime number''' (or simply '''prime''') is a [[positive integer]] <math>p>1</math> whose only positive [[divisor | divisors]] are 1 and itself. |
Note that <math>1</math> is usually defined as being neither prime nor composite because it is its only factor among the [[natural number|natural numbers]]. | Note that <math>1</math> is usually defined as being neither prime nor composite because it is its only factor among the [[natural number|natural numbers]]. | ||
Revision as of 23:35, 19 June 2006
A prime number (or simply prime) is a positive integer whose only positive divisors are 1 and itself. Note that is usually defined as being neither prime nor composite because it is its only factor among the natural numbers.
Contents
[hide]Famous Primes
Fermat Primes
Mersenne Primes
Twin Primes
Two primes that differ by exactly 2 are known as twin primes. The following are the smallest examples: 3, 5 5, 7 11, 13 17, 19 29, 31 41, 43
Advanced Definition
When the need arises to include negative divisors, a prime is defined as an integer p whose only divisors are 1, -1, p, and -p.