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        riddles >> medium >> Determine all positive integers
        
(Message started by: tony123 on Nov 17^th, 2007, 2:02am)

Title: Determine all positive integers
Post by tony123 on Nov 17^th, 2007, 2:02am

Determine all positive integers a and b such that x^2 + x + 1 divides

x^a + x^b + 1

Title: Re: Determine all positive integers
Post by Aryabhatta on Nov 17^th, 2007, 3:17pm

I get [hide] a + b = 0 (mod 3) and a =\= 0 (mod 3) by considering the complex cube roots of unity. [/hide]