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A161930 Number of reduced words of length n in the Weyl group B_23. 1


%S 1,23,275,2277,14673,78407,361514,1477750,5461235,18518565,58282576,

%T 171815888,477989151,1262643305,3183445871,7694405993,17895700206,

%U 40182143330,87349858045,184297593435,378236260170,756560791350

%N Number of reduced words of length n in the Weyl group B_23.

%C Computed with MAGMA using commands similar to those used to compute A161409.

%D J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincaré polynomial.

%D N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche II.)

%F 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.

%K nonn

%O 0,2

%A _John Cannon_ and _N. J. A. Sloane_, Nov 30 2009

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Last modified June 18 00:21 EDT 2021. Contains 345088 sequences. (Running on oeis4.)