# 2003 Combination Sum

Discrete Mathematics Level 4

$\large\dbinom{2003}1+\dbinom{2003}4+\dbinom{2003}7+\ldots+\dbinom{2003}{2002}=k(2^{2002}-1)$

If the value of $$k$$ can be represented by $$\dfrac{a}{b}$$ when $$a$$ and $$b$$ are coprime positive integers, find $$a+b$$.

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