A091687 Number of lattice congruences of the weak order on the Coxeter group S_n (the symmetric group).

1, 2, 7, 60, 3444, 11402948, 129187106461769

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: A352625 A308681 A366328 * 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