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A165308
Number of reduced words of length n in Coxeter group on 16 generators S_i with relations (S_i)^2 = (S_i S_j)^9 = I.
0
1, 16, 240, 3600, 54000, 810000, 12150000, 182250000, 2733750000, 41006249880, 615093746400, 9226406169120, 138396092133600, 2075941375956000, 31139120548620000, 467086806868500000, 7006302082615500000
OFFSET
0,2
COMMENTS
The initial terms coincide with those of A170735, although the two sequences are eventually different.
Computed with MAGMA using commands similar to those used to compute A154638.
FORMULA
G.f. (t^9 + 2*t^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t +
1)/(105*t^9 - 14*t^8 - 14*t^7 - 14*t^6 - 14*t^5 - 14*t^4 - 14*t^3 -
14*t^2 - 14*t + 1)
MATHEMATICA
coxG[{9, 105, -14}] (* The coxG program is at A169452 *) (* Harvey P. Dale, Aug 14 2021 *)
CROSSREFS
Sequence in context: A164627 A164867 A063814 * A165876 A166410 A166584
KEYWORD
nonn
AUTHOR
John Cannon and N. J. A. Sloane, Dec 03 2009
STATUS
approved