|
|
A161438
|
|
Number of reduced words of length n in the Weyl group A_6.
|
|
1
|
|
|
1, 6, 20, 49, 98, 169, 259, 359, 455, 531, 573, 573, 531, 455, 359, 259, 169, 98, 49, 20, 6, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
(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
|
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..89.
|
|
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: A203552 A331754 A050768 * A063488 A299292 A162209
Adjacent sequences: A161435 A161436 A161437 * A161439 A161440 A161441
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
John Cannon and N. J. A. Sloane, Nov 30 2009
|
|
STATUS
|
approved
|
|
|
|