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Number of reduced words of length n in Coxeter group on 43 generators S_i with relations (S_i)^2 = (S_i S_j)^7 = I.
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%I #12 Feb 25 2024 09:09:26

%S 1,43,1806,75852,3185784,133802928,5619722976,236028364089,

%T 9913191253812,416354031068115,17486869237997292,734448505187617668,

%U 30846837099932661024,1295567153243385959664,54413820228163207379946

%N Number of reduced words of length n in Coxeter group on 43 generators S_i with relations (S_i)^2 = (S_i S_j)^7 = I.

%C The initial terms coincide with those of A170762, 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_07">Index entries for linear recurrences with constant coefficients</a>, signature (41, 41, 41, 41, 41, 41, -861).

%F G.f.: (t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(861*t^7 - 41*t^6 - 41*t^5 - 41*t^4 - 41*t^3 - 41*t^2 - 41*t + 1).

%t coxG[{7,861,-41}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Aug 30 2016 *)

%K nonn

%O 0,2

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