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 A162211 Number of reduced words of length n in the Weyl group D_8. 0
 1, 8, 35, 112, 293, 664, 1350, 2520, 4388, 7208, 11263, 16848, 24248, 33712, 45425, 59480, 75853, 94384, 114766, 136544, 159125, 181800, 203777, 224224, 242318, 257296, 268504, 275440, 277788, 275440, 268504, 257296, 242318, 224224, 203777 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Computed with MAGMA using commands similar to those used to compute A161409. REFERENCES N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche IV.) J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under PoincarĂ© polynomial. LINKS FORMULA 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. CROSSREFS The growth series for D_k, k >= 5, are A162208-A162212, A162248, A162288, A162297. The growth series for D_k, k >= 3, are also the rows of the triangle A162206. Sequence in context: A006600 A161456 A005732 * A161717 A162494 A040977 Adjacent sequences:  A162208 A162209 A162210 * A162212 A162213 A162214 KEYWORD nonn AUTHOR John Cannon and N. J. A. Sloane, Dec 01 2009 STATUS approved

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Last modified October 21 08:27 EDT 2018. Contains 316405 sequences. (Running on oeis4.)