Solution
= Solution
For an odd <prime number> $p$, the <Legendre symbol> $(a/p)$ is zero if $p\mid a$, is $+1$ if $a$ is a nonzero square modulo $p$, and is $-1$ otherwise.
= Solution
For an odd <prime number> $p$, the <Legendre symbol> $(a/p)$ is zero if $p\mid a$, is $+1$ if $a$ is a nonzero square modulo $p$, and is $-1$ otherwise.