divisibility

[margot]

well this is the question... if a,m and n are positive integers with m<n, then (a^(2^m)+1) is a divisor of (a^(2^n)-1)... I started using induction and it works for the first step... but for the second one i do not know if i can make induction on m... any hint would help.. thanks :)

[Petek]

Hint: Can you prove the result if n = m + 1?

Please post again if this doesn't help or if you'd like another hint.

Petek