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A091687 Number of lattice congruences of the weak order on the Coxeter group S_n (the symmetric group). 4
1, 2, 7, 60, 3444, 11402948, 129187106461769 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

To a very good approximation for n=4,5,6 we have a(n+1) ~ (a(n))^2.

LINKS

Table of n, a(n) for n=1..7.

Nathan Reading, Lattice congruences of the weak order, arXiv:math/0401404 [math.CO], 2004.

CROSSREFS

Cf. A091688, A330039.

Sequence in context: A215209 A274600 A308681 * A000892 A211875 A065397

Adjacent sequences:  A091684 A091685 A091686 * A091688 A091689 A091690

KEYWORD

nonn,hard,more

AUTHOR

Nathan Reading (nreading(AT)umich.edu), Jan 28 2004

STATUS

approved

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Last modified December 1 16:44 EST 2021. Contains 349430 sequences. (Running on oeis4.)