Mathematics.General Mathematics Section

Mathematics Forum

Author	Message / Information
cramwit Quote \| Reply \|	Is a complete prime list as factors + 1 = prime? posted on: 3/30/2007 7:36:39 AM If you take the complete list of primes up to Pn [2,3,5,7,11,13, . . . ,Pn] multiply them, then add one, is that a prime? ( 2 * 3 * 5 * 7 * 11 * 13 * ...* Pn ) + 1 = a prime? You could calculate & check all the primes from Pn to sqrt(Product) for a pair of factors. And since you have used all the smaller potential prime factors a set of 3 or more factors is almost impossible. I am just wondering if anyone else thinks this might be true, & if there is a way of proving [or disproving] it? If it is true, it would be a way of manufacturing [very] large prime numbers. Also i was wondering if a pair of bounding primes are of any use determining the primes that lie between them?
cramwit Quote \| Reply \|	Is a complete prime list as factors + 1 = prime? replied on: 4/1/2007 8:54:08 AM Oops. I should have checked this before posting. It fails at: 2 * 3 * 5 * 7 * 11 * 13 + 1 = 30031 = 59 * 509
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