A162193 Number of reduced words of length n in the Weyl group B_48.

1, 48, 1175, 19552, 248723, 2579312, 22706404, 174482000, 1194358970, 7396268880, 41942496051, 219939217728, 1075086490926, 4931595192160, 21350092231441, 87658196804688, 342762976614961, 1281150739056160

Offset: 0

Author

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

Keywords

• nonn

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 Poincaré polynomial.
• N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche II.)

Formula

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.