Possible Duplicate:
Accuracy of Fermat's Little Theorem?
$n$ is odd and composite number,and there exists $b_0$ , $0
prove that there are at least 50% of numbers $b$ such that $0 and $gcd(b,n)=1$ which satisfy ${b_0}^{n-1} \not \equiv {1} \mod{n}$
Possible Duplicate:
Accuracy of Fermat's Little Theorem?
$n$ is odd and composite number,and there exists $b_0$ , $0
prove that there are at least 50% of numbers $b$ such that $0 and $gcd(b,n)=1$ which satisfy ${b_0}^{n-1} \not \equiv {1} \mod{n}$