TheScienceGeek

What about this formula... if (x-1)!/x is an integer the no. x is not a prime no. :::::::: or else ...it is !?! [exception is no. 4]

I would like to know is there an existing formula to find prime nos. ?? In either case I have come up with a formula... x/(x-1)! where x is the given no. to be checked !! the ratio x/(x-1)! should be in its lowest terms by default ... also x should not equal to 2 !! then and only then it is a prime no. !!