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Search: id:A141473
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| A141473 |
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Number of 3-equitable permutations: permutations on n letters equally avoiding each permutation of S_3. (e.g. 2143 contains 214, 213--213 permutations-- and 243 and 143--both 132 permutations. |
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+0
1
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OFFSET
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3,1
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COMMENT
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A permutation is 3-equitable if no \omega \in S_3 appears more than ceil(binomial(n,3)/6) times and no fewer than floor(binomial(n,3)/6) times).
This is a generalization of the Kendall-Mann numbers A000140.
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LINKS
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Sunil Abraham, Maple program
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EXAMPLE
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The only 3-equitable permutations in S_4: [3, 1, 4, 2], [2, 4, 1, 3].
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CROSSREFS
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Cf. A000140.
Sequence in context: A138186 A110321 A111553 this_sequence A068931 A061666 A136708
Adjacent sequences: A141470 A141471 A141472 this_sequence A141474 A141475 A141476
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KEYWORD
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hard,more,nonn
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AUTHOR
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Sunil Abraham (sunil.abraham(AT)lmh.ox.ac.uk), Aug 08 2008
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