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A163802
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Number of reduced words of length n in Coxeter group on 46 generators S_i with relations (S_i)^2 = (S_i S_j)^5 = I.
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1
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1, 46, 2070, 93150, 4191750, 188627715, 8488200600, 381966932160, 17188417679400, 773474553522000, 34806164017265190, 1566268790718951000, 70481709031863535560, 3171659511757241439000, 142723895272921025613000
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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 A170765, 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^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(990*t^5 - 44*t^4 - 44*t^3 - 44*t^2 - 44*t + 1).
a(n) = 44*a(n-1)+44*a(n-2)+44*a(n-3)+44*a(n-4)-990*a(n-5). - Wesley Ivan Hurt, May 11 2021
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MAPLE
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seq(coeff(series((1+t)*(1-t^5)/(1-45*t+1034*t^5-990*t^6), t, n+1), t, n), n = 0 .. 20); # G. C. Greubel, Aug 09 2019
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MATHEMATICA
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CoefficientList[Series[(1+t)*(1-t^5)/(1-45*t+1034*t^5-990*t^6), {t, 0, 20}], t] (* G. C. Greubel, Aug 04 2017 *)
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PROG
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(PARI) my(t='t+O('t^20)); Vec((1+t)*(1-t^5)/(1-45*t+1034*t^5-990*t^6)) \\ G. C. Greubel, Aug 04 2017
(Magma) R<t>:=PowerSeriesRing(Integers(), 20); Coefficients(R!( (1+t)*(1-t^5)/(1-45*t+1034*t^5-990*t^6) )); // G. C. Greubel, Aug 09 2019
(Sage)
P.<t> = PowerSeriesRing(ZZ, prec)
return P((1+t)*(1-t^5)/(1-45*t+1034*t^5-990*t^6)).list()
(GAP) a:=[46, 2070, 93150, 4191750, 188627715];; for n in [6..30] do a[n]:=44*(a[n-1]+a[n-2]+a[n-3]+a[n-4]) -990*a[n-5]; od; Concatenation([1], a); # G. C. Greubel, Aug 09 2019
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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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