--- Jean-So?=bastien Bour <[EMAIL PROTECTED]> wrote: > Matthias Kilian a icrit : > > a) 4 is the first non-prime, at least according to factor(6). > > > No, it is 1 :) > Explanation : a prime number can only be divided by two different > numbers : 1 and itself. 1 can only be divided by one number, > therefore it is not prime.
Wrong. You got the definition of what a prime number is wrong. A prime number is defined as a positive integer greater than one which has positive divisors 1 and itself, only. Please note that using your definition 7 is not prime because -7, -1, 1 and 7 all divide 7. I suggest at least looking into elementary number theory before making such statements again. Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com