%I #6 Dec 03 2025 17:11:30

%S 1,28,756,20034,530712,14054040,372171618,9855587196,260988761124,

%T 6911320818402,183020737961880,4846626473132808,128344953881202786,

%U 3398740810188105564,90003063973732401492,2383397845569631005570

%N Number of reduced words of length n in Coxeter group on 28 generators S_i with relations (S_i)^2 = (S_i S_j)^3 = I.

%C The initial terms coincide with those of A170747, 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 (26, 26, -351).

%F G.f.: (t^3 + 2*t^2 + 2*t + 1)/(351*t^3 - 26*t^2 - 26*t + 1)

%K nonn

%O 0,2

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