|
|
A162920
|
|
Number of reduced words of length n in Coxeter group on 3 generators S_i with relations (S_i)^2 = (S_i S_j)^4 = I.
|
|
0
|
|
|
1, 3, 6, 12, 21, 36, 63, 108, 186, 321, 552, 951, 1638, 2820, 4857, 8364, 14403, 24804, 42714, 73557, 126672, 218139, 375654, 646908, 1114029, 1918452, 3303735, 5689308, 9797466, 16872057, 29055096, 50035311, 86164998, 148383348
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
COMMENTS
|
The initial terms coincide with those of A003945, although the two sequences are eventually different.
Computed with MAGMA using commands similar to those used to compute A154638.
|
|
LINKS
|
|
|
FORMULA
|
G.f.: (t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(t^4 - t^3 - t^2 - t + 1)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|