Solve this congruence equation

For students of class 9-10 (age 14-16)
User avatar
Phlembac Adib Hasan
Posts:1016
Joined:Tue Nov 22, 2011 7:49 pm
Location:127.0.0.1
Contact:
Solve this congruence equation

Unread post by Phlembac Adib Hasan » Wed Jan 23, 2013 10:32 pm

Find all positive integers n such that $2^{n-1} \equiv -1 \pmod{n}$.
Welcome to BdMO Online Forum. Check out Forum Guides & Rules

User avatar
Phlembac Adib Hasan
Posts:1016
Joined:Tue Nov 22, 2011 7:49 pm
Location:127.0.0.1
Contact:

Re: Solve this congruence equation

Unread post by Phlembac Adib Hasan » Thu Jan 24, 2013 12:20 pm

Nobody interested? Well I'm giving a hint.
Think about order and Fermat's little theorem.
Welcome to BdMO Online Forum. Check out Forum Guides & Rules

User avatar
zadid xcalibured
Posts:217
Joined:Thu Oct 27, 2011 11:04 am
Location:mymensingh

Re: Solve this congruence equation

Unread post by zadid xcalibured » Thu Jan 24, 2013 6:18 pm

Still not interested. $SIGH$
btw,Happy Birthday.

Post Reply