cp's OEIS Frontend

A170020 Number of reduced words of length n in Coxeter group on 11 generators S_i with relations (S_i)^2 = (S_i S_j)^36 = I.

%I A170020 #6 Nov 26 2016 09:40:08
%S A170020 1,11,110,1100,11000,110000,1100000,11000000,110000000,1100000000,
%T A170020 11000000000,110000000000,1100000000000,11000000000000,
%U A170020 110000000000000,1100000000000000,11000000000000000,110000000000000000
%N A170020 Number of reduced words of length n in Coxeter group on 11 generators S_i with relations (S_i)^2 = (S_i S_j)^36 = I.
%C A170020 The initial terms coincide with those of A003953, although the two sequences are eventually different.
%C A170020 Computed with MAGMA using commands similar to those used to compute A154638.
%H A170020 <a href="/index/Rec#order_36">Index entries for linear recurrences with constant coefficients</a>, signature (9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, -45).
%F A170020 G.f. (t^36 + 2*t^35 + 2*t^34 + 2*t^33 + 2*t^32 + 2*t^31 + 2*t^30 + 2*t^29 +
%F A170020 2*t^28 + 2*t^27 + 2*t^26 + 2*t^25 + 2*t^24 + 2*t^23 + 2*t^22 + 2*t^21 +
%F A170020 2*t^20 + 2*t^19 + 2*t^18 + 2*t^17 + 2*t^16 + 2*t^15 + 2*t^14 + 2*t^13 +
%F A170020 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
%F A170020 + 2*t^3 + 2*t^2 + 2*t + 1)/(45*t^36 - 9*t^35 - 9*t^34 - 9*t^33 - 9*t^32
%F A170020 - 9*t^31 - 9*t^30 - 9*t^29 - 9*t^28 - 9*t^27 - 9*t^26 - 9*t^25 - 9*t^24
%F A170020 - 9*t^23 - 9*t^22 - 9*t^21 - 9*t^20 - 9*t^19 - 9*t^18 - 9*t^17 - 9*t^16
%F A170020 - 9*t^15 - 9*t^14 - 9*t^13 - 9*t^12 - 9*t^11 - 9*t^10 - 9*t^9 - 9*t^8 -
%F A170020 9*t^7 - 9*t^6 - 9*t^5 - 9*t^4 - 9*t^3 - 9*t^2 - 9*t + 1)
%K A170020 nonn
%O A170020 0,2
%A A170020 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009