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A141473 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. 1
6, 2, 2, 0, 0, 4, 2, 0, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,1

COMMENTS

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.

LINKS

Table of n, a(n) for n=3..11.

Sunil Abraham, Maple program

EXAMPLE

The only 3-equitable permutations in S_4: [3, 1, 4, 2], [2, 4, 1, 3].

CROSSREFS

Cf. A000140.

Sequence in context: A138186 A110321 A111553 * A068931 A061666 A136708

Adjacent sequences:  A141470 A141471 A141472 * A141474 A141475 A141476

KEYWORD

hard,more,nonn

AUTHOR

Sunil Abraham (sunil.abraham(AT)lmh.ox.ac.uk), Aug 08 2008

STATUS

approved

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Last modified November 18 22:39 EST 2019. Contains 329305 sequences. (Running on oeis4.)