A161991 - OEIS

%I #5 Jul 19 2015 10:23:32

%S 1,34,594,7106,65449,494768,3195983,18134478,92219577,426746308,

%T 1818523916,7204803796,26747139312,93651006988,310966484313,

%U 983825011398,2977708459669,8652371731716,24211251121429,65420187465158

%N Number of reduced words of length n in the Weyl group B_34.

%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