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A168760 Number of reduced words of length n in Coxeter group on 35 generators S_i with relations (S_i)^2 = (S_i S_j)^18 = I.

%I A168760 #14 Nov 24 2016 14:00:16
%S A168760 1,35,1190,40460,1375640,46771760,1590239840,54068154560,
%T A168760 1838317255040,62502786671360,2125094746826240,72253221392092160,
%U A168760 2456609527331133440,83524723929258536960,2839840613594790256640,96554580862222868725760
%N A168760 Number of reduced words of length n in Coxeter group on 35 generators S_i with relations (S_i)^2 = (S_i S_j)^18 = I.
%C A168760 The initial terms coincide with those of A170754, although the two sequences are eventually different.
%C A168760 First disagreement at index 18: a(18) = 3794981246208807632397270445, A170754(18) = 3794981246208807632397271040. - _Klaus Brockhaus_, Mar 26 2011
%C A168760 Computed with MAGMA using commands similar to those used to compute A154638.
%H A168760 G. C. Greubel, <a href="/A168760/b168760.txt">Table of n, a(n) for n = 0..500</a>
%H A168760 <a href="/index/Rec#order_18">Index entries for linear recurrences with constant coefficients</a>, signature (33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, -561).
%F A168760 G.f.: (t^18 + 2*t^17 + 2*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)/(561*t^18 - 33*t^17 - 33*t^16 - 33*t^15 - 33*t^14 - 33*t^13 - 33*t^12 - 33*t^11 - 33*t^10 - 33*t^9 - 33*t^8 - 33*t^7 - 33*t^6 - 33*t^5 - 33*t^4 - 33*t^3 - 33*t^2 - 33*t + 1).
%t A168760 CoefficientList[Series[(t^18 + 2*t^17 + 2*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)/(561*t^18 - 33*t^17 - 33*t^16 - 33*t^15 - 33*t^14 - 33*t^13 - 33*t^12 - 33*t^11 - 33*t^10 - 33*t^9 - 33*t^8 - 33*t^7 - 33*t^6 - 33*t^5 - 33*t^4 - 33*t^3 - 33*t^2 - 33*t + 1), {t, 0, 50}], t] (* _G. C. Greubel_, Aug 11 2016 *)
%Y A168760 Cf. A170754 (G.f.: (1+x)/(1-34*x)).
%K A168760 nonn,easy
%O A168760 0,2
%A A168760 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009