# Commuting in Manhattan

A man walks $$n$$ blocks north and $$n$$ blocks west of his residence to get to work. As they are installing a sewage pipe diagonally across town, he can touch, but cannot cross over, the main diagonal line.

The above figure shows $$84$$ possible paths he could take for $$n=5$$.

How many possible routes can he take if $$n=28$$?

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