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A161475
Number of reduced words of length n in the Weyl group A_14.
0
1, 14, 104, 545, 2260, 7889, 24087, 66013, 165425, 384320, 836604, 1720774, 3366951, 6301715, 11333950, 19664205, 33018831, 53808313, 85306779, 131846699, 199019426, 293868698, 425060810, 603012233, 839953393, 1149906518
OFFSET
0,2
COMMENTS
Computed with MAGMA using commands similar to those used to compute A161409.
REFERENCES
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.)
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.
CROSSREFS
Sequence in context: A295210 A255721 A089508 * A162301 A161862 A266561
KEYWORD
nonn
AUTHOR
John Cannon and N. J. A. Sloane, Nov 30 2009
STATUS
approved