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A161530
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Number of reduced words of length n in the Weyl group A_27.
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0
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1, 27, 377, 3626, 26999, 165852, 874755, 4071079, 17052724, 65259715, 230856472, 761987905, 2364726003, 6943746516, 19395654894, 51770913911, 132567002957, 326758146932, 777583981286, 1791153918119, 4003030425506, 8697839966552
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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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