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A162389 Number of reduced words of length n in the Weyl group D_37. 0
1, 37, 702, 9102, 90686, 740222, 5153693, 31465577, 171895451, 853189623, 3893872009, 16498746405, 65414952123, 244293496151, 864100862802, 2908662063474, 9355685557836, 28857543077604, 85625485744207 (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 Poincaré polynomial.

LINKS

Table of n, a(n) for n=0..18.

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

Sequence in context: A010953 A161650 A162165 * A010989 A103195 A282927

Adjacent sequences:  A162386 A162387 A162388 * A162390 A162391 A162392

KEYWORD

nonn

AUTHOR

John Cannon and N. J. A. Sloane, Dec 01 2009

STATUS

approved

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Last modified March 20 19:23 EDT 2019. Contains 321349 sequences. (Running on oeis4.)