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 A166617 #11 Nov 24 2016 09:42:06
%S A166617 1,30,870,25230,731670,21218430,615334470,17844699630,517496289270,
%T A166617 15007392388830,435214379276070,12621216999006030,366015292971174435,
%U A166617 10614443496164046000,307818861388756968600,8926746980273941492800
%N A166617 Number of reduced words of length n in Coxeter group on 30 generators S_i with relations (S_i)^2 = (S_i S_j)^12 = I.
%C A166617 The initial terms coincide with those of A170749, although the two sequences are eventually different.
%C A166617 Computed with MAGMA using commands similar to those used to compute A154638.
%H A166617 G. C. Greubel, <a href="/A166617/b166617.txt">Table of n, a(n) for n = 0..500</a>
%H A166617 <a href="/index/Rec#order_12">Index entries for linear recurrences with constant coefficients</a>, signature (28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, -406).
%F A166617 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)/(406*t^12 - 28*t^11 - 28*t^10 - 28*t^9 -28*t^8 -28*t^7 - 28*t^6 - 28*t^5 - 28*t^4 - 28*t^3 - 28*t^2 - 28*t +1).
%t A166617 coxG[{12,406,-28}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Jan 21 2015 *)
%t A166617 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)/(406*t^12 - 28*t^11 - 28*t^10 - 28*t^9 - 28*t^8 - 28*t^7 - 28*t^6 - 28*t^5 - 28*t^4 - 28*t^3 - 28*t^2 - 28*t + 1), {t, 0, 50}], t] (* _G. C. Greubel_, May 19 2016 *)
%K A166617 nonn
%O A166617 0,2
%A A166617 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009