# Another Summation

Algebra Level 5

$\large\displaystyle\sum_{n=8}^{ \infty}\dfrac{1}{(n-4)(n-2)n(n+2)(n+4)}$

The summation above is equal to $$\dfrac{a}{b}$$, where $$\text{gcd}(a,b) = 1$$. Find $$a+b$$.

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