Factorial Primes
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Basic Info
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Discovered by | N/A |
Number of | Conjectured infinite |
Description | A prime which is either one more or one less than a factorial |
First Few | 2, 3, 5, 7, 23, 719,2,309,2,311 |
Factorial Primes are prime numbers that can be expressed in the form n!±1, ie they are prime numbers that are one bigger or smaller than a factorial number. A factorial number is a number that is made by multiplying consecutive numbers, starting with 1, eg 3!=1*2*3. Both 5 and 7 are factorial primes because they complete the rule 3!±1.