Quote:
Originally Posted by literka
I started to read this link and I am totally confused. On the page 2 there is equality
2^{(Fn1)/2} = 1 (mod Fn)
where Fn denotes Fermat number.
Take n=1. Then
Fn=F_{1}=5,
(Fn1)/2 = 2, 2^2=4 and
4 is not equal 1 modulo 5.
Am I missing something?

Yes , you have missed condition :