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A164639
Number of reduced words of length n in Coxeter group on 26 generators S_i with relations (S_i)^2 = (S_i S_j)^7 = I.
0
1, 26, 650, 16250, 406250, 10156250, 253906250, 6347655925, 158691390000, 3967284547200, 99182108610000, 2479552588500000, 61988811543750000, 1549720209375000000, 38743003253906355300, 968575031835945300000
OFFSET
0,2
COMMENTS
The initial terms coincide with those of A170745, although the two sequences are eventually different.
Computed with MAGMA using commands similar to those used to compute A154638.
FORMULA
G.f.: (t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(300*t^7 - 24*t^6 - 24*t^5 - 24*t^4 - 24*t^3 - 24*t^2 - 24*t + 1).
MATHEMATICA
coxG[{7, 300, -24}] (* The coxG program is at A169452 *) (* Harvey P. Dale, Feb 04 2015 *)
CROSSREFS
Sequence in context: A163177 A163526 A163995 * A164964 A165369 A165973
KEYWORD
nonn
AUTHOR
John Cannon and N. J. A. Sloane, Dec 03 2009
STATUS
approved