|
|
A161636
|
|
Number of reduced words of length n in the Weyl group A_31.
|
|
0
|
|
|
1, 31, 495, 5424, 45848, 318649, 1895464, 9919009, 46584724, 199347764, 786519756, 2888400232, 9950014727, 32360135292, 99903188872, 294134516323, 829176461458, 2245909515022, 5862798149046, 14789460753680, 36138546144580
(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
|
|
|
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
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|