Determine whether or not N is a composite number, where

NOTE:
A prime number (or a prime) is a natural number that has exactly two (distinct) natural number divisors, which are 1 and the prime number itself. A composite number is a positive integer which has a positive divisor other than one or itself. By definition, every integer greater than one is either a prime number or a composite number. The numbers 0 and 1 are considered to be neither prime nor composite.

N = (26^2 - 1)26^21 + (26^2 + 1)26^10 - 1 =
26^23 - 26^21 + 26^12 + 26^10 - 1 =
(26^11 - 26^10 + 1)(26^12 + 26^11 - 1),
which is is composite as both sides are clearly greater than 1.

Posted by Nick Hobson on 2006-04-23 18:29:27