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Number of reduced words of length n in the Weyl group A_41.
0

%I #5 Jul 19 2015 10:30:01

%S 1,41,860,12299,134848,1208516,9217866,61521649,366624707,1980976460,

%T 9822684102,45131469838,193676694825,781450953227,2981168796829,

%U 10804753100301,37358311880918,123672795559348,393238376839063

%N Number of reduced words of length n in the Weyl group A_41.

%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 I.)

%F 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.

%K nonn

%O 0,2

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