

A161679


Number of reduced words of length n in the Weyl group A_44.


0



1, 44, 989, 15135, 177330, 1696090, 13789281, 97978552, 620888610, 3563495915, 18748484569, 91307324410, 414916710263, 1771027595355, 7140808776515, 27329013354044, 99693953208860, 347908423900311, 1165210802267460
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OFFSET

0,2


COMMENTS

Computed with MAGMA using commands similar to those used to compute A161409.


REFERENCES

J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under PoincarĂ© polynomial.
N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche I.)


LINKS

Table of n, a(n) for n=0..18.


FORMULA

G.f. for A_m is the polynomial Prod_{k=1..m}(1x^(k+1))/(1x). Only finitely many terms are nonzero. This is a row of the triangle in A008302.


CROSSREFS

Sequence in context: A010960 A035717 A035611 * A162182 A162413 A010996
Adjacent sequences: A161676 A161677 A161678 * A161680 A161681 A161682


KEYWORD

nonn


AUTHOR

John Cannon and N. J. A. Sloane, Nov 30 2009


STATUS

approved



