# Factorial Series

Calculus Level 4

$\large\dfrac{1!}{4!}+\dfrac{2!}{5!}+\dfrac{3!}{6!}+\dfrac{4!}{7!}+\cdots$

If the value of the above series can be expressed to $$\dfrac{a}{b}$$ when $$a$$ and $$b$$ are coprime positive integers. Find the value of $$a+b$$.

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