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 A161437 Number of reduced words of length n in the Weyl group A_5. 0
 1, 5, 14, 29, 49, 71, 90, 101, 101, 90, 71, 49, 29, 14, 5, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 (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 J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under PoincarĂ© polynomial. N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche I.) LINKS FORMULA 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. MATHEMATICA CoefficientList[Series[(1 - x^2) (1 - x^3) (1 - x^4) (1 - x^5) (1 - x^6) / (1 - x)^5, {x, 0, 120}], x] (* Vincenzo Librandi, Aug 23 2016 *) CROSSREFS Sequence in context: A244100 A031333 A303706 * A301681 A047801 A005918 Adjacent sequences:  A161434 A161435 A161436 * A161438 A161439 A161440 KEYWORD nonn AUTHOR John Cannon and N. J. A. Sloane, Nov 30 2009 STATUS approved

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Last modified November 19 05:29 EST 2018. Contains 317333 sequences. (Running on oeis4.)