A161458 Number of reduced words of length n in the Weyl group A_10.

1, 10, 54, 209, 649, 1717, 4015, 8504, 16599, 30239, 51909, 84591, 131625, 196470, 282369, 391939, 526724, 686763, 870233, 1073227, 1289718, 1511742, 1729808, 1933514, 2112319, 2256396, 2357475, 2409581, 2409581, 2357475, 2256396, 2112319, 1933514, 1729808, 1511742

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 Poincaré polynomial.

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

Links

Andrew Howroyd, Table of n, a(n) for n = 0..55

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.

Crossrefs

Row n=11 of A008302.

Sequence in context: A219169 A292058 A152762 * A162248 A161755 A053347

Adjacent sequences: A161455 A161456 A161457 * A161459 A161460 A161461

Keyword

nonn,fini,full

Author

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

Status

approved