Can a Group Have a Cyclic Automorphism Group of Odd Order?

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Homework Statement



Prove that no group can have its automorphism group cyclic of odd order.

Homework Equations





The Attempt at a Solution



Aut(Z2) has order 1, which is odd...trivial, yes, but I thought I was DONE.

However, my professor has said "well prove it EXCEPT for Z2"

I thought I was done, and now I have till 2 to do redo this and I have a mental block on it.

Can someone give my a push?

Thanks,
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So you've got to show that every group (except Z/2Z) with cyclic aut. grp. has an automorphism of order 2...
 
All right, I think I see it now...although I already turned it in incomplete. I just couldn't see it yesterday.
Thanks.