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A163093
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Number of reduced words of length n in Coxeter group on 17 generators S_i with relations (S_i)^2 = (S_i S_j)^4 = I.
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0
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1, 17, 272, 4352, 69496, 1109760, 17721480, 282988800, 4518961080, 72161899200, 1152331158600, 18401221627200, 293843444945400, 4692295538064000, 74929823330517000, 1196531288107632000, 19107039891249747000, 305114439575750760000, 4872278582526960045000
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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 A170736, 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^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(120*t^4 - 15*t^3 - 15*t^2 - 15*t + 1).
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MATHEMATICA
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CoefficientList[Series[(t^4 + 2 t^3 + 2 t^2 + 2 t + 1)/(120 t^4 - 15 t^3 - 15 t^2 - 15 t + 1), {t, 0, 20}], t] (* Jinyuan Wang, Mar 23 2020 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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