|
Search: id:A162168
|
|
|
| A162168 |
|
Number of reduced words of length n in the Weyl group B_39. |
|
+0
1
|
|
| 1, 39, 779, 10621, 111149, 951899, 6946342, 44406362, 253761833, 1316306927, 6272724030, 27727887538, 114598003169, 445761614951, 1641026089535, 5744952627593, 19204564723487, 61521719896985, 189464360814690
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
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 Poincare 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.
|
|
CROSSREFS
|
Sequence in context: A059609 A010955 A161652 this_sequence A162399 A126927 A010991
Adjacent sequences: A162165 A162166 A162167 this_sequence A162169 A162170 A162171
|
|
KEYWORD
|
nonn,new
|
|
AUTHOR
|
John Cannon (john(AT)maths.usyd.edu.au) and N. J. A. Sloane (njas(AT)research.att.com), Nov 30 2009
|
|
|
Search completed in 0.002 seconds
|
