perplexus.info :: Probability : (x!+1)/(x+1) = prime number

(x!+1)/(x+1) = prime number (Posted on 2010-07-30)

For a positive integer x drawn at random between 1 and 20000 inclusively, determine the probability that (x!+1)/(x+1) is a prime number.

No Solution Yet Submitted by K Sengupta

Rating: 2.3333 (3 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)

re: search is over

Comment 9 of 9 |

(In reply to search is over by Daniel)

Daniel:

I like this corrected proof. Much more elegant than what I would have done to rehabilitate your original almost-proof. Nice work!

Steve

Posted by Steve Herman on 2010-08-01 13:03:06

Please log in:

Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (0)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:


perplexus dot info