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 A167956 #15 Jul 14 2023 08:48:44
%S A167956 1,40,1560,60840,2372760,92537640,3608967960,140749750440,
%T A167956 5489240267160,214080370419240,8349134446350360,325616243407664040,
%U A167956 12699033492898897560,495262306223057004840,19315229942699223188760
%N A167956 Number of reduced words of length n in Coxeter group on 40 generators S_i with relations (S_i)^2 = (S_i S_j)^16 = I.
%C A167956 The initial terms coincide with those of A170759, although the two sequences are eventually different.
%C A167956 Computed with Magma using commands similar to those used to compute A154638.
%H A167956 G. C. Greubel, <a href="/A167956/b167956.txt">Table of n, a(n) for n = 0..500</a>
%H A167956 <a href="/index/Rec#order_16">Index entries for linear recurrences with constant coefficients</a>, signature (38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,-741).
%F A167956 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)/( 741*t^16 - 38*t^15 - 38*t^14 - 38*t^13 - 38*t^12 - 38*t^11 - 38*t^10 - 38*t^9 - 38*t^8 - 38*t^7 - 38*t^6 - 38*t^5 - 38*t^4 - 38*t^3 - 38*t^2 - 38*t + 1).
%F A167956 From _G. C. Greubel_, Jul 14 2023: (Start)
%F A167956 G.f.: (1 + t)*(1 - t^16)/(1 - 39*t + 779*t^16 - 741*t^17).
%F A167956 a(n) = -741*a(n-16) + 38*Sum_{j=1..15} a(n-j). (End)
%t A167956 CoefficientList[Series[(1+t)*(1-t^16)/(1-39*t+779*t^16-741*t^17), {t, 0, 40}], t] (* _G. C. Greubel_, Jul 02 2016; Jul 14 2023 *)
%t A167956 coxG[{16,741,-38}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Jun 22 2019 *)
%o A167956 (Magma) R<x>:=PowerSeriesRing(Integers(), 40); Coefficients(R!( (1+x)*(1-x^16)/(1-39*x+779*x^16-741*x^17) )); // _G. C. Greubel_, Jul 14 2023
%o A167956 (SageMath)
%o A167956 def A167956_list(prec):
%o A167956 P.<x> = PowerSeriesRing(ZZ, prec)
%o A167956 return P( (1+x)*(1-x^16)/(1-39*x+779*x^16-741*x^17) ).list()
%o A167956 A167956_list(40) # _G. C. Greubel_, Jul 14 2023
%Y A167956 Cf. A154638, A169452, A170759.
%K A167956 nonn
%O A167956 0,2
%A A167956 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009