# Not Wallis Product

Algebra Level 4

$1 + \frac {1}{5} + \frac {1 \times 3}{5 \times 10} + \frac {1 \times 3 \times 5}{5 \times 10 \times 15} + \cdots$

The series above can be expressed in the for of $$\sqrt{ \dfrac a b }$$, where $$a$$ and $$b$$ are coprime positive integers.

What is the value of $$a+b$$?

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