20030516, 14:41  #1 
487 Posts 
The first (nonmerseinne) 10 milliondigit prime number!!!
If this qualifies for the contest for $100,000, then let GIMPS do with the money as they see fit.
Since by adding 1 to N! gives a prime number (N! + 1 cannot be factored by any number =<N), this is a simple matter of finding a factorial which has 10 million digits  the first of which being 1,737,441. This gives a prime of 10 million and 1 (I think) digits, with the last digit a 1. (Still computing the value, could take a couple of months :(). 1,737,411!+1 = xxx...xx 1. If, however, you need a Merseinne prime, then I have none. Good luck in the search!!! 
20030516, 14:55  #2 
Dec 2002
Frederick County, MD
2·5·37 Posts 
Well, you have to look at all numbers <= to N!+1 to try to find a factor, not just numbers <=N.
Ex) 4! + 1 = 2*3*4 + 1 = 25, and 5 divides 25. In fact, I'm not even sure if a prime number exists of the form N! + 1 for N >= 4. However, in reference to the other part of your post, a 10M digit prime does not need to be a Mersenne prime to qualify for the prize. EDIT: 11! + 1 is prime, but who knows if there are a finite numbers of primes in this form or not? (I'm sure someone knows.) 
20030516, 15:24  #3 
Dec 2002
Frederick County, MD
2·5·37 Posts 
OK, here's the link for Factorial prime information:
http://www.utm.edu/research/primes/l...Factorial.html 
20030519, 23:11  #4  
∂^{2}ω=0
Sep 2002
República de California
11,399 Posts 
Re: The first (nonmerseinne) 10 milliondigit prime number!
Quote:
Now, if one knew every prime <= R (the current record holder), one could form the product of all these, add or subtract one, and the result would be guaranteed to have no factors <= R, i.e. one would have implicitly found a new recordsize prime. One can do similar stuff like this with Mersennes: if R is the largestknown Mersenne prime, then 2^R  1 has no factors < 2*R+1, i.e. is either an even bigger prime or decomposes into factors bigger than R. But these types of constructions don't qualify for recordprime status: that requires an EXPLICIT prime. Looks like the EFF gets to hold on to their $100K for a little while longer. 

20030607, 21:34  #5 
Jun 2003
The Computer
2^{2}·5·19 Posts 
Yeah it's harder than that you'd probably have to try Prime95 on that exponent.

20040225, 10:28  #6  
Bronze Medalist
Jan 2004
Mumbai,India
2^{2}·3^{3}·19 Posts 
Factorial primes
Quote:
http://mathworld.wolfram.com/WilsonsTheorem.html Mfgoode 

20040225, 11:07  #7 
Dec 2003
Hopefully Near M48
11011011110_{2} Posts 
It is not always true that (2^M)1, where M is a mersenne prime, is itself prime. MM15 and MM31 are not prime.

20040226, 23:26  #8 
Aug 2002
110110_{2} Posts 
Nice try Ron.
It would be nice to win $100K so keep at it. 
20040227, 23:20  #9  
Jun 2003
Pa.,U.S.A.
2^{2}·7^{2} Posts 
Not so fast
Quote:
It appears by a limiting technique on an algorithm of finding a kp=2^(p1)1, (try finding k of kp=2^(p1)1, with 5,7,11,13,...by a method of accumulating a continuous sum of powers of two for the product, and step by step, filling in the powers of two for k. The limit involves p.) ie fermat test , that 10,001,631 is prime, unless pseudo prime: Anyone wish to find a witness,etc., or show (10001630)!/(10001631) is even, if no witness occurs(tough) or the above division is not even, then the number IS prime. 

20040228, 08:17  #10 
Mar 2003
3^{4} Posts 
Вut (10^10,000,000)!+1 defenetly contains a prime factor > 10,000,000 digits long.

20040228, 15:41  #11  
Bronze Medalist
Jan 2004
Mumbai,India
2^{2}×3^{3}×19 Posts 
non mersenne primes.
Quote:
You have brought up an interesting point on Mersenne primes. However your comment bears no relevance to the topic under discussion. Ron clearly states about “non mersenne” primes and primes formed from factorials. That’s why I have referred him to Wilsons theorem and given the link to explore further. As a ready reference Wilsons theorem states that for any prime one has the formula (p1)! = 1 (mod p). This is not true if p is composite and must be prime. For larger primes this formula is not practical and involves a lot of computation even for a computer. That’s why Mersenne prime formulae are preffered over Wilsons. At the same time Wilsons theorem is both necessary and sufficient for primality. As the number of primes is infinite and this formula involves primes it gives an infinite number of results. Mally. 

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