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2012-04-02, 09:03   #8
princeps

Nov 2011

22×3 Posts

Quote:
 Originally Posted by literka I started to read this link and I am totally confused. On the page 2 there is equality 2(Fn-1)/2 = 1 (mod Fn) where Fn denotes Fermat number. Take n=1. Then Fn=F1=5, (Fn-1)/2 = 2, 2^2=4 and 4 is not equal 1 modulo 5. Am I missing something?
Yes , you have missed condition : $n \geq 2$