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A342811
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Volume of the permutohedron obtained from the coordinates 1, 2, 4, ..., 2^(n-1), multiplied by (n-1)!.
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1
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1, 13, 1009, 354161, 496376001, 2632501072321, 52080136110870785, 3872046158193220660993, 1099175272489026844687825921, 1210008580962784935280673680079873, 5225407816779297641534116390319222362113
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OFFSET
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2,2
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COMMENTS
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Here the volume is relative to the unit cell of the lattice which is the intersection of Z^n with the hyperplane spanning the polytope.
a(n) is the number of subgraphs of the complete bipartite graph K_{n-1,n} such that for any vertex from the 2nd part there is a matching that covers all other vertices; Postnikov calls the characterization of such subgraphs "the dragon marriage problem".
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LINKS
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MATHEMATICA
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a[n_] := Sum[(p.(2^Range[0, n-1]))^(n-1) / Times @@ Differences[p], {p, Permutations@Range@n}];
Table[a[n], {n, 2, 8}]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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