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%I #5 Jul 19 2015 10:22:39
%S 1,38,740,9842,100528,840750,5994443,37460020,209355471,1062545094,
%T 4956417103,21455163508,86870115631,331163611782,1195264474584,
%U 4103926538058,13459612095894,42317155173498,127942640917705
%N Number of reduced words of length n in the Weyl group B_38.
%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