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A162205
Number of reduced words of length n in the Weyl group B_50.
0
1, 50, 1274, 22050, 291549, 3140360, 28695575, 228732790, 1623128975, 10413794040, 61146955156, 331819334000, 1677578203770, 7954932265700, 35582378559071, 150868021657130, 608916641370150, 2348116000139330
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 II.)
FORMULA
G.f. for B_m is the polynomial Product_{k=1..m}(1-x^(2k))/(1-x). Only finitely many terms are nonzero. This is a row of the triangle in A128084.
CROSSREFS
Cf. A128084.
Sequence in context: A187459 A035720 A161695 * A162492 A017713 A283311
KEYWORD
nonn
AUTHOR
John Cannon and N. J. A. Sloane, Nov 30 2009
STATUS
approved