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 A167944 #17 Sep 07 2023 18:11:48
%S A167944 1,29,812,22736,636608,17825024,499100672,13974818816,391294926848,
%T A167944 10956257951744,306775222648832,8589706234167296,240511774556684288,
%U A167944 6734329687587160064,188561231252440481792,5279714475068333490176
%N A167944 Number of reduced words of length n in Coxeter group on 29 generators S_i with relations (S_i)^2 = (S_i S_j)^16 = I.
%C A167944 The initial terms coincide with those of A170748, although the two sequences are eventually different.
%C A167944 Computed with MAGMA using commands similar to those used to compute A154638.
%H A167944 G. C. Greubel, <a href="/A167944/b167944.txt">Table of n, a(n) for n = 0..500</a>
%H A167944 <a href="/index/Rec#order_16">Index entries for linear recurrences with constant coefficients</a>, signature (27,27,27,27,27,27,27,27,27,27,27,27,27,27,27,-378).
%F A167944 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)/( 378*t^16 - 27*t^15 - 27*t^14 - 27*t^13 - 27*t^12 - 27*t^11 - 27*t^10 - 27*t^9 - 27*t^8 - 27*t^7 - 27*t^6 - 27*t^5 - 27*t^4 - 27*t^3 - 27*t^2 - 27*t + 1).
%F A167944 From _G. C. Greubel_, Sep 07 2023: (Start)
%F A167944 G.f.: (1+t)*(1-t^16)/(1 - 28*t + 405*t^16 - 378*t^17).
%F A167944 a(n) = 27*Sum_{j=1..15} a(n-j) - 378*a(n-16). (End)
%t A167944 coxG[{16,378,-27}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Feb 16 2016 *)
%t A167944 CoefficientList[Series[(1+t)*(1-t^16)/(1-28*t+405*t^16-378*t^17), {t, 0, 50}], t] (* _G. C. Greubel_, Jul 02 2016; Sep 07 2023 *)
%o A167944 (Magma) R<x>:=PowerSeriesRing(Integers(), 40); Coefficients(R!( (1+x)*(1-x^16)/(1-28*x+405*x^16-378*x^17) )); // _G. C. Greubel_, Sep 07 2023
%o A167944 (SageMath)
%o A167944 def A167944_list(prec):
%o A167944 P.<x> = PowerSeriesRing(ZZ, prec)
%o A167944 return P( (1+x)*(1-x^16)/(1-28*x+405*x^16-378*x^17) ).list()
%o A167944 A167944_list(40) # _G. C. Greubel_, Sep 07 2023
%Y A167944 Cf. A154638, A169452, A170748.
%K A167944 nonn
%O A167944 0,2
%A A167944 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009