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A161931 Number of reduced words of length n in the Weyl group B_24. 0
1, 24, 299, 2576, 17249, 95656, 457170, 1934920, 7396155, 25914720, 84197296, 256013184, 734002335, 1996645640, 5180091511, 12874497504, 30770197710, 70952341040, 158302199085, 342599792520, 720836052690, 1477396844040 (list; graph; refs; listen; history; text; internal format)
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.)

LINKS

Table of n, a(n) for n=0..21.

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.

CROSSREFS

Sequence in context: A281134 A128598 A161524 * A162366 A153782 A073990

Adjacent sequences:  A161928 A161929 A161930 * A161932 A161933 A161934

KEYWORD

nonn

AUTHOR

John Cannon and N. J. A. Sloane, Nov 30 2009

STATUS

approved

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Last modified June 24 07:45 EDT 2021. Contains 345416 sequences. (Running on oeis4.)