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 A167945 #20 Sep 07 2023 18:20:16
%S A167945 1,30,870,25230,731670,21218430,615334470,17844699630,517496289270,
%T A167945 15007392388830,435214379276070,12621216999006030,366015292971174870,
%U A167945 10614443496164071230,307818861388758065670,8926746980273983904430
%N A167945 Number of reduced words of length n in Coxeter group on 30 generators S_i with relations (S_i)^2 = (S_i S_j)^16 = I.
%C A167945 The initial terms coincide with those of A170749, although the two sequences are eventually different.
%C A167945 Computed with MAGMA using commands similar to those used to compute A154638.
%H A167945 G. C. Greubel, <a href="/A167945/b167945.txt">Table of n, a(n) for n = 0..500</a>
%H A167945 <a href="/index/Rec#order_16">Index entries for linear recurrences with constant coefficients</a>, signature (28,28,28,28,28,28,28,28,28,28,28,28,28,28,28,-406).
%F A167945 G.f.: (t^16 + 2*t^15 + 2*t^14 + 2*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)/( 406*t^16 - 28*t^15 - 28*t^14 - 28*t^13 - 28*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).
%F A167945 From _G. C. Greubel_, Sep 07 2023: (Start)
%F A167945 G.f.: (1+t)*(1-t^16)/(1 - 29*t + 434*t^16 - 406*t^17).
%F A167945 a(n) = 28*Sum_{j=1..15} a(n-j) - 406*a(n-16). (End)
%t A167945 CoefficientList[Series[(1+t)*(1-t^16)/(1-29*t+434*t^16-406*t^17), {t, 0, 50}], t] (* _G. C. Greubel_, Jul 02 2016; Sep 07 2023 *)
%t A167945 coxG[{16,406,-28}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Dec 15 2017 *)
%o A167945 (Magma) R<x>:=PowerSeriesRing(Integers(), 40); Coefficients(R!( (1+x)*(1-x^16)/(1-29*x+434*x^16-406*x^17) )); // _G. C. Greubel_, Sep 07 2023
%o A167945 (SageMath)
%o A167945 def A167945_list(prec):
%o A167945 P.<x> = PowerSeriesRing(ZZ, prec)
%o A167945 return P( (1+x)*(1-x^16)/(1-29*x+434*x^16-406*x^17) ).list()
%o A167945 A167945_list(40) # _G. C. Greubel_, Sep 07 2023
%Y A167945 Cf. A154638, A169452, A170749.
%K A167945 nonn
%O A167945 0,2
%A A167945 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009