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%I #8 Nov 23 2016 22:16:45
%S 1,40,1560,60840,2372760,92537640,3608967960,140749750440,
%T 5489240267160,214080370418460,8349134446289520,325616243404105680,
%U 12699033492713883120,495262306214038144080,19315229942277159012720
%N Number of reduced words of length n in Coxeter group on 40 generators S_i with relations (S_i)^2 = (S_i S_j)^9 = I.
%C The initial terms coincide with those of A170759, 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_09">Index entries for linear recurrences with constant coefficients</a>, signature (38, 38, 38, 38, 38, 38, 38, 38, -741).
%F G.f. (t^9 + 2*t^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t +
%F 1)/(741*t^9 - 38*t^8 - 38*t^7 - 38*t^6 - 38*t^5 - 38*t^4 - 38*t^3 -
%F 38*t^2 - 38*t + 1)
%t coxG[{9,741,-38}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Apr 13 2016 *)
%K nonn
%O 0,2
%A _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009