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Results tagged with co.combinatorics
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user 3648
Enumerative combinatorics, graph theory, order theory, posets, matroids, designs and other discrete structures. It also includes algebraic, analytic and probabilistic combinatorics.
5
votes
Help with a double sum, please
Some observations.
Define
$$T(N)=\binom{2N}{N}\sum_{j=0}^{N-1}\left[\binom{2(N-j)}{N-j} \cdot (N-j) \cdot 2^{(N+j+1)}\right]^{-1}.$$
Then
$$S(m)=\sum_{k=0}^m (-1)^k \binom{m}{k} T(m+k) .$$
Experimen …
