%I
%S 1,17,272,4352,69496,1109760,17721480,282988800,4518961080,
%T 72161899200,1152331158600,18401221627200,293843444945400,
%U 4692295538064000,74929823330517000,1196531288107632000,19107039891249747000
%N 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.
%C The initial terms coincide with those of A170736, 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 (15, 15, 15, 120).
%F 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)
%K nonn
%O 0,2
%A _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009
