A161648 Number of reduced words of length n in the Weyl group A_35.

1, 35, 629, 7734, 73149, 567322, 3756165, 21824599, 113542269, 537026584, 2336914709, 9446244041, 35748066704, 127485570114, 430805130559, 1385987640650, 4262490454456, 12575680441068, 35703722618623

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

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

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

Sequence in context: A208617 A010951 A033281 * A162149 A162384 A126925

Adjacent sequences: A161645 A161646 A161647 * A161649 A161650 A161651

Keyword

nonn

Author

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

Status

approved