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A165180
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Number of reduced words of length n in Coxeter group on 48 generators S_i with relations (S_i)^2 = (S_i S_j)^8 = I.
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0
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1, 48, 2256, 106032, 4983504, 234224688, 11008560336, 517402335792, 24317909781096, 1142941759658496, 53718262701458688, 2524758346851499008, 118663642296518664960, 5577191187677793197568, 262127985808702829674752
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OFFSET
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0,2
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COMMENTS
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The initial terms coincide with those of A170767, although the two sequences are eventually different.
Computed with MAGMA using commands similar to those used to compute A154638.
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LINKS
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FORMULA
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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)/(1081*t^8 - 46*t^7 - 46*t^6 - 46*t^5 - 46*t^4 - 46*t^3 - 46*t^2 - 46*t + 1).
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MATHEMATICA
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With[{num=Total[2t^Range[7]]+t^8+1, den=Total[-46 t^Range[7]]+1081t^8+ 1}, CoefficientList[Series[num/den, {t, 0, 30}], t]] (* Harvey P. Dale, Jul 27 2011 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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