

A161646


Number of reduced words of length n in the Weyl group A_33.


0



1, 33, 560, 6511, 58310, 428758, 2694670, 14879591, 73649236, 331766645, 1376403810, 5309441207, 19192493331, 65435680747, 211582057035, 651862949646, 1921320303715, 5436687172806, 14814852190943, 38982477962760
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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..19.


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: A342199 A002608 A010949 * A161988 A162380 A188357
Adjacent sequences: A161643 A161644 A161645 * A161647 A161648 A161649


KEYWORD

nonn


AUTHOR

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


STATUS

approved



