A161862 Number of reduced words of length n in the Weyl group B_14.

1, 14, 104, 546, 2274, 7994, 24647, 68392, 173978, 411332, 913445, 1921218, 3852849, 7407596, 13716315, 24553998, 42632552, 71995170, 118536730, 190677578, 300220648, 463423974, 702322075, 1046330260, 1534165425, 2216115226, 3156684454, 4437642874, 6161492611, 8455365296

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 II.)

J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincaré polynomial.

Links

Andrew Howroyd, Table of n, a(n) for n = 0..196

Formula

G.f. for B_m is the polynomial Product_{k=1..m} (1-x^(2k))/(1-x). Only finitely many terms are nonzero. This is a row of the triangle in A128084.

Crossrefs

Row n=14 of A128084.

Sequence in context: A089508 A161475 A162301 * A266561 A370962 A222369

Adjacent sequences: A161859 A161860 A161861 * A161863 A161864 A161865

Keyword

nonn,fini,full,easy

Author

John Cannon and N. J. A. Sloane, Nov 30 2009

Status

approved