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 A166613 #11 Oct 14 2018 18:42:19
%S A166613 1,26,650,16250,406250,10156250,253906250,6347656250,158691406250,
%T A166613 3967285156250,99182128906250,2479553222656250,61988830566405925,
%U A166613 1549720764160140000,38743019104003297200,968575477600077360000
%N A166613 Number of reduced words of length n in Coxeter group on 26 generators S_i with relations (S_i)^2 = (S_i S_j)^12 = I.
%C A166613 The initial terms coincide with those of A170745, although the two sequences are eventually different.
%C A166613 Computed with MAGMA using commands similar to those used to compute A154638.
%H A166613 G. C. Greubel, <a href="/A166613/b166613.txt">Table of n, a(n) for n = 0..500</a>
%H A166613 <a href="/index/Rec#order_12">Index entries for linear recurrences with constant coefficients</a>, signature (24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, -300).
%F A166613 G.f.: (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)/(300*t^12 - 24*t^11 - 24*t^10 - 24*t^9 -24*t^8 -24*t^7 - 24*t^6 - 24*t^5 - 24*t^4 - 24*t^3 - 24*t^2 -24*t + 1).
%t A166613 CoefficientList[Series[(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)/(300*t^12 - 24*t^11 - 24*t^10 - 24*t^9 - 24*t^8 - 24*t^7 - 24*t^6 - 24*t^5 - 24*t^4 - 24*t^3 - 24*t^2 - 24*t + 1), {t, 0, 50}], t] (* _G. C. Greubel_, May 19 2016 *)
%t A166613 coxG[{12,300,-24}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Oct 14 2018 *)
%K A166613 nonn
%O A166613 0,2
%A A166613 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009