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A164684
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Number of reduced words of length n in Coxeter group on 40 generators S_i with relations (S_i)^2 = (S_i S_j)^7 = I.
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0
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1, 40, 1560, 60840, 2372760, 92537640, 3608967960, 140749749660, 5489240206320, 214080366860880, 8349134261335920, 325616234388803280, 12699033070834721520, 495262287019738489680, 19315229086799991370740
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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 A170759, 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^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(741*t^7 - 38*t^6 - 38*t^5 - 38*t^4 - 38*t^3 - 38*t^2 - 38*t + 1).
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MATHEMATICA
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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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