Prove that the numbers that begin with 1 and end with 1, with any number of 2s in the middle, and all 1s and 2s separated by 00 are composite.

For example:
1002001
1002002001,
1002002002001,
1002002002002001

(In reply to A solution by Brian Smith)

This was something cool I thought up, but it was better suited for a morning problem because its "All are divisible by 1001" solution is so easy. :)

Posted by Gamer on 2003-10-10 15:57:28