# My Favorite Number is 1153

Number Theory Level 5

If the maximum power of 5 in $$n!$$ is $$k_n$$ (For example $$k_{10}=2$$ since $$10!=2^8×3^4×5^2×7$$), find the value of $\displaystyle \sum_{n=1}^{1153}{[k_n×(-1)^{n+1}]}$

This is one part of 1+1 is not = to 3.

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