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A162413 Number of reduced words of length n in the Weyl group D_44. 0


%S 1,44,989,15136,177374,1697080,13804461,98156916,622600869,3577478696,

%T 18848352755,91943892924,418593879770,1790510819500,7236416033496,

%U 27766992285908,101579448507141,355579239690840,1194844427708580

%N Number of reduced words of length n in the Weyl group D_44.

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

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

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

%F G.f. for D_m is the polynomial f(n) * Product( f(2i), i=1..n-1 )/ f(1)^n, where f(k) = 1-x^k. Only finitely many terms are nonzero. This is a row of the triangle in A162206.

%K nonn

%O 0,2

%A _John Cannon_ and _N. J. A. Sloane_, Dec 01 2009

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Last modified May 8 22:05 EDT 2021. Contains 343668 sequences. (Running on oeis4.)