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.

Since 26²=676, we have N=
(26²-1)26²¹+ (26²+1)26¹⁰-1=
26²³-26²¹+26¹²+26¹⁰-1.

And for now, that's as far as I got... I tried mod 3, mod 5, mod 7, but it didn't work.

Posted by e.g. on 2006-04-23 12:10:50