This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A166950 #12 Dec 22 2023 19:21:36
%S A166950 1,11,110,1100,11000,110000,1100000,11000000,110000000,1100000000,
%T A166950 11000000000,110000000000,1100000000000,10999999999945,
%U A166950 109999999998900,1099999999983555,10999999999781100,109999999997266500
%N A166950 Number of reduced words of length n in Coxeter group on 11 generators S_i with relations (S_i)^2 = (S_i S_j)^13 = I.
%C A166950 The initial terms coincide with those of A003953, although the two sequences are eventually different.
%C A166950 Computed with MAGMA using commands similar to those used to compute A154638.
%H A166950 G. C. Greubel, <a href="/A166950/b166950.txt">Table of n, a(n) for n = 0..500</a>
%H A166950 <a href="/index/Rec#order_13">Index entries for linear recurrences with constant coefficients</a>, signature (9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, -45).
%F A166950 G.f.: (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)/(45*t^13 - 9*t^12 - 9*t^11 - 9*t^10 - 9*t^9 - 9*t^8 - 9*t^7 - 9*t^6 - 9*t^5 - 9*t^4 - 9*t^3 - 9*t^2 - 9*t + 1).
%t A166950 CoefficientList[Series[(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)/(45*t^13 - 9*t^12 - 9*t^11 - 9*t^10 - 9*t^9 - 9*t^8 - 9*t^7 - 9*t^6 - 9*t^5 - 9*t^4 - 9*t^3 - 9*t^2 - 9*t + 1), {t, 0, 50}], t] (* _G. C. Greubel_, May 28 2016 *)
%t A166950 coxG[{13,45,-9}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Dec 22 2023 *)
%K A166950 nonn
%O A166950 0,2
%A A166950 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009