cp's OEIS Frontend

A170114 Number of reduced words of length n in Coxeter group on 9 generators S_i with relations (S_i)^2 = (S_i S_j)^38 = I.

%I A170114 #6 May 14 2017 17:30:51
%S A170114 1,9,72,576,4608,36864,294912,2359296,18874368,150994944,1207959552,
%T A170114 9663676416,77309411328,618475290624,4947802324992,39582418599936,
%U A170114 316659348799488,2533274790395904,20266198323167232,162129586585337856
%N A170114 Number of reduced words of length n in Coxeter group on 9 generators S_i with relations (S_i)^2 = (S_i S_j)^38 = I.
%C A170114 The initial terms coincide with those of A003951, although the two sequences are eventually different.
%C A170114 Computed with MAGMA using commands similar to those used to compute A154638.
%H A170114 <a href="/index/Rec#order_38">Index entries for linear recurrences with constant coefficients</a>, signature (7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, -28).
%F A170114 G.f. (t^38 + 2*t^37 + 2*t^36 + 2*t^35 + 2*t^34 + 2*t^33 + 2*t^32 + 2*t^31 +
%F A170114 2*t^30 + 2*t^29 + 2*t^28 + 2*t^27 + 2*t^26 + 2*t^25 + 2*t^24 + 2*t^23 +
%F A170114 2*t^22 + 2*t^21 + 2*t^20 + 2*t^19 + 2*t^18 + 2*t^17 + 2*t^16 + 2*t^15 +
%F A170114 2*t^14 + 2*t^13 + 2*t^12 + 2*t^11 + 2*t^10 + 2*t^9 + 2*t^8 + 2*t^7 +
%F A170114 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(28*t^38 - 7*t^37 -
%F A170114 7*t^36 - 7*t^35 - 7*t^34 - 7*t^33 - 7*t^32 - 7*t^31 - 7*t^30 - 7*t^29 -
%F A170114 7*t^28 - 7*t^27 - 7*t^26 - 7*t^25 - 7*t^24 - 7*t^23 - 7*t^22 - 7*t^21 -
%F A170114 7*t^20 - 7*t^19 - 7*t^18 - 7*t^17 - 7*t^16 - 7*t^15 - 7*t^14 - 7*t^13 -
%F A170114 7*t^12 - 7*t^11 - 7*t^10 - 7*t^9 - 7*t^8 - 7*t^7 - 7*t^6 - 7*t^5 - 7*t^4
%F A170114 - 7*t^3 - 7*t^2 - 7*t + 1)
%K A170114 nonn
%O A170114 0,2
%A A170114 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009