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A161653
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Number of reduced words of length n in the Weyl group A_40.
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0
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1, 40, 819, 11439, 122549, 1073668, 8009350, 52303783, 305103058, 1614351753, 7841707642, 35308785736, 148545224987, 587774258402, 2199717843602, 7823584303472, 26553558780617, 86314483678430, 269565581279715
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OFFSET
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0,2
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COMMENTS
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Computed with MAGMA using commands similar to those used to compute A161409.
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REFERENCES
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J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincaré polynomial.
N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche I.)
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LINKS
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FORMULA
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G.f. for A_m is the polynomial Prod_{k=1..m}(1-x^(k+1))/(1-x). Only finitely many terms are nonzero. This is a row of the triangle in A008302.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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