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{\bf M.D. Atkinson} \medskip\noindent
{\bf Permutations which are the union of an increasing and a decreasing
subsequence}
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It is shown that there are ${2n\choose
n}-\sum_{m=0}^{n-1}2^{n-m-1}{2m\choose m}$ permutations which are the union of
an increasing sequence and a decreasing sequence.


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