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 re: Divisibility by SilverKnight)

When you do the multiplication of 1001 times 1001, 1001001, so on, you will see this:

    1001


 1001   


 1002001





       1001


    1001


 1001      


 1002002001

That's about it.

Posted by Gamer on 2003-10-10 17:02:44