%I #20 Sep 06 2023 17:31:06
%S 1,36,1260,44100,1543500,54022500,1890787500,66177562500,
%T 2316214687500,81067514062500,2837362992187500,99307704726562500,
%U 3475769665429687500,121651938290039062500,4257817840151367187500,149023624405297851562500
%N Number of reduced words of length n in Coxeter group on 36 generators S_i with relations (S_i)^2 = (S_i S_j)^16 = I.
%C The initial terms coincide with those of A170755, although the two sequences are eventually different.
%C Computed with MAGMA using commands similar to those used to compute A154638.
%H G. C. Greubel, <a href="/A167952/b167952.txt">Table of n, a(n) for n = 0..500</a>
%H <a href="/index/Rec#order_16">Index entries for linear recurrences with constant coefficients</a>, signature (34,34,34,34,34,34,34,34,34,34,34,34,34,34,34,-595).
%F G.f.: (t^16 + 2*t^15 + 2*t^14 + 2*t^13 + 2*t^12 + 2*t^11 + 2*t^10 + 2*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 + 1)/( 595*t^16 - 34*t^15 - 34*t^14 - 34*t^13 - 34*t^12 - 34*t^11 - 34*t^10 - 34*t^9 - 34*t^8 - 34*t^7 - 34*t^6 - 34*t^5 - 34*t^4 - 34*t^3 - 34*t^2 - 34*t + 1).
%F From _G. C. Greubel_, Sep 06 2023: (Start)
%F G.f.: (1+t)*(1-t^16)/(1 - 35*t + 629*t^16 - 595*t^17).
%F a(n) = 34*Sum_{j=1..15} a(n-j) - 595*a(n-16). (End)
%t coxG[{16,595,-34}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Apr 07 2015 *)
%t CoefficientList[Series[(1+t)*(1-t^16)/(1-35*t+629*t^16-595*t^17), {t, 0, 50}], t] (* _G. C. Greubel_, Jul 02 2016; Sep 06 2023 *)
%o (Magma) R<x>:=PowerSeriesRing(Integers(), 40); Coefficients(R!( (1+x)*(1-x^16)/(1-35*x+629*x^16-595*x^17) )); // _G. C. Greubel_, Sep 06 2023
%o (SageMath)
%o def A167955_list(prec):
%o P.<x> = PowerSeriesRing(ZZ, prec)
%o return P( (1+x)*(1-x^16)/(1-35*x+629*x^16-595*x^17) ).list()
%o A167955_list(40) # _G. C. Greubel_, Sep 06 2023
%Y Cf. A154638, A169452, A170755.
%K nonn
%O 0,2
%A _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009
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