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%I #7 Oct 28 2023 10:37:11
%S 1,5,20,80,310,1200,4650,18000,69690,269820,1044630,4044420,15658470,
%T 60623640,234711810,908715240,3518201250,13621143060,52735907790,
%U 204173464860,790482339630,3060448278480,11848896802170,45874441471680
%N Number of reduced words of length n in Coxeter group on 5 generators S_i with relations (S_i)^2 = (S_i S_j)^4 = I.
%C The initial terms coincide with those of A003947, although the two sequences are eventually different.
%C Computed with MAGMA using commands similar to those used to compute A154638.
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (3, 3, 3, -6).
%F G.f.: (t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(6*t^4 - 3*t^3 - 3*t^2 - 3*t + 1)
%t coxG[{4,6,-3,30}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Oct 28 2023 *)
%K nonn
%O 0,2
%A _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009
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