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A116693
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Number of fixed-point-free subgroups of the symmetric group S_n.
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2
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1, 0, 1, 2, 15, 50, 874, 3515, 94638, 634630, 18368060, 149965474, 7392944314, 61596293433, 4042125261152, 46326163964879, 4045711099761347, 47868661342996788, 6066544790946772416
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OFFSET
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0,4
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LINKS
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MATHEMATICA
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A005432 = Cases[Import["https://oeis.org/A005432/b005432.txt", "Table"], {_, _}][[All, 2]];
a[n_] := Sum[(-1)^(n-k) Binomial[n, k] A005432[[k+1]], {k, 0, n}];
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CROSSREFS
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KEYWORD
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nonn,hard
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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