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A164867
Number of reduced words of length n in Coxeter group on 16 generators S_i with relations (S_i)^2 = (S_i S_j)^8 = I.
0
1, 16, 240, 3600, 54000, 810000, 12150000, 182250000, 2733749880, 41006246400, 615093669120, 9226404633600, 138396063456000, 2075940861120000, 31139111556000000, 467086652928000000, 7006299487740014280
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^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(105*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[{8, 105, -14}] (* The coxG program is at A169452 *) (* Harvey P. Dale, Mar 16 2015 *)
CROSSREFS
Sequence in context: A163441 A163964 A164627 * A063814 A165308 A165876
KEYWORD
nonn
AUTHOR
John Cannon and N. J. A. Sloane, Dec 03 2009
STATUS
approved