|
|
A163179
|
|
Number of reduced words of length n in Coxeter group on 27 generators S_i with relations (S_i)^2 = (S_i S_j)^4 = I.
|
|
0
|
|
|
1, 27, 702, 18252, 474201, 12320100, 320085675, 8316067500, 216057716550, 5613342710625, 145838884522500, 3789004401804375, 98441196968058750, 2557576669978687500, 66447774146243953125, 1726363373899181062500
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
COMMENTS
|
The initial terms coincide with those of A170746, 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)/(325*t^4 - 25*t^3 - 25*t^2 - 25*t + 1).
|
|
PROG
|
(PARI) Vec((t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(325*t^4 - 25*t^3 - 25*t^2 - 25*t + 1) + O(t^20)) \\ Jinyuan Wang, Mar 23 2020
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|