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A161525
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Number of reduced words of length n in the Weyl group A_25.
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0
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1, 25, 324, 2899, 20124, 115480, 570050, 2487421, 9785321, 35225346, 117389766, 365534676, 1071606665, 2976282415, 7872887865, 19923350639, 48420830029, 113395054929, 256634690379, 562744102479, 1198306570554, 2482933033659
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Computed with MAGMA using commands similar to those used to compute A161409.
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REFERENCES
| J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincare polynomial.
N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche I.)
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FORMULA
| 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
| Sequence in context: A171445 A053805 A125437 * A161932 A162367 A077503
Adjacent sequences: A161522 A161523 A161524 * A161526 A161527 A161528
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KEYWORD
| nonn
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AUTHOR
| John Cannon (john(AT)maths.usyd.edu.au) and N. J. A. Sloane (njas(AT)research.att.com), Nov 30 2009
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