# Gauss won't help

$\large\sum_{n=1}^{10007}\left(\frac{n(n+1)}{10009}\right) = \, ?$

Note: In above summation expression , $$\large \left( \frac{a}{b} \right)$$ denotes the Legendre symbol and it is not an ordinary fraction.

Bonus: Generalize this for arbitary odd primes.

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