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A161991
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Number of reduced words of length n in the Weyl group B_34.
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0
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1, 34, 594, 7106, 65449, 494768, 3195983, 18134478, 92219577, 426746308, 1818523916, 7204803796, 26747139312, 93651006988, 310966484313, 983825011398, 2977708459669, 8652371731716, 24211251121429, 65420187465158
(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 II.)
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FORMULA
| G.f. for B_m is the polynomial Prod_{k=1..m}(1-x^(2k))/(1-x). Only finitely many terms are nonzero. This is a row of the triangle in A128084.
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CROSSREFS
| Sequence in context: A035712 A161647 * A162381 A010986 A004418 A020928
Adjacent sequences: A161988 A161989 A161990 * A161992 A161993 A161994
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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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