

A161573


Number of reduced words of length n in the Weyl group A_30.


0



1, 30, 464, 4929, 40424, 272801, 1576815, 8023545, 36665715, 152763040, 587171992, 2101880476, 7061614495, 22410120565, 67543053580, 194231327451, 535041945135, 1416733053564, 3616888634024, 8926662604634, 21349085390900
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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..20.


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: A281700 A024524 A081736 * A161976 A162377 A162736
Adjacent sequences: A161570 A161571 A161572 * A161574 A161575 A161576


KEYWORD

nonn


AUTHOR

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


STATUS

approved



