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Number of reduced words of length n in Coxeter group on 6 generators S_i with relations (S_i)^2 = (S_i S_j)^3 = I.
0

%I #5 Nov 23 2016 15:15:41

%S 1,6,30,135,600,2640,11610,51000,224040,984060,4322400,18985440,

%T 83390760,366280800,1608831840,7066542960,31038691200,136332618240,

%U 598819808160,2630222793600,11552844224640,50744069991360

%N Number of reduced words of length n in Coxeter group on 6 generators S_i with relations (S_i)^2 = (S_i S_j)^3 = I.

%C The initial terms coincide with those of A003948, 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_03">Index entries for linear recurrences with constant coefficients</a>, signature (4, 4, -10).

%F G.f.: (t^3 + 2*t^2 + 2*t + 1)/(10*t^3 - 4*t^2 - 4*t + 1)

%K nonn

%O 0,2

%A _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009