Revision History for A161694
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#5 by Jon E. Schoenfield at Sun Jul 19 10:28:55 EDT 2015
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#4 by Jon E. Schoenfield at Sun Jul 19 10:28:54 EDT 2015
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| REFERENCES
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J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincare Poincaré polynomial.
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| STATUS
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approved
editing
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#3 by N. J. A. Sloane at Sun Jul 13 09:05:25 EDT 2014
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| AUTHOR
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_John Cannon (john(AT)maths.usyd.edu.au) _ and N. J. A. Sloane, Nov 30 2009
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Discussion
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| Sun Jul 13
| 09:05
| OEIS Server: https://oeis.org/edit/global/2246
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#2 by Russ Cox at Fri Mar 30 16:51:25 EDT 2012
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| AUTHOR
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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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Discussion
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| Fri Mar 30
| 16:51
| OEIS Server: https://oeis.org/edit/global/110
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#1 by N. J. A. Sloane at Tue Jun 01 03:00:00 EDT 2010
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| NAME
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Number of reduced words of length n in the Weyl group A_49.
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| DATA
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1, 49, 1224, 20775, 269450, 2847586, 25534390, 199766491, 1391526550, 8764839175, 50530255490, 269252177545, 1336765568579, 6225203548375, 27347806169775, 113887933772724, 451493020193130, 1710182996663175
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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 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
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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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| KEYWORD
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nonn
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| AUTHOR
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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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| STATUS
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approved
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