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 A167954 #15 Sep 06 2023 17:19:16
%S A167954 1,38,1406,52022,1924814,71218118,2635070366,97497603542,
%T A167954 3607411331054,133474219248998,4938546112212926,182726206151878262,
%U A167954 6760869627619495694,250152176221921340678,9255630520211089605086
%N A167954 Number of reduced words of length n in Coxeter group on 38 generators S_i with relations (S_i)^2 = (S_i S_j)^16 = I.
%C A167954 The initial terms coincide with those of A170757, although the two sequences are eventually different.
%C A167954 Computed with MAGMA using commands similar to those used to compute A154638.
%H A167954 G. C. Greubel, <a href="/A167954/b167954.txt">Table of n, a(n) for n = 0..500</a>
%H A167954 <a href="/index/Rec#order_16">Index entries for linear recurrences with constant coefficients</a>, signature (36,36,36,36,36,36,36,36,36,36,36,36,36,36,36,-666).
%F A167954 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)/( 666*t^16 - 36*t^15 - 36*t^14 - 36*t^13 - 36*t^12 - 36*t^11 - 36*t^10 - 36*t^9 - 36*t^8 - 36*t^7 - 36*t^6 - 36*t^5 - 36*t^4 - 36*t^3 - 36*t^2 - 36*t + 1).
%F A167954 From _G. C. Greubel_, Sep 06 2023: (Start)
%F A167954 G.f.: (1+t)*(1-t^16)/(1 - 37*t + 702*t^16 - 666*t^17).
%F A167954 a(n) = 36*Sum_{j=1..15} a(n-j) - 666*a(n-16). (End)
%t A167954 CoefficientList[Series[(1+t)*(1-t^16)/(1-37*t+702*t^16-666*t^17), {t, 0, 50}], t] (* _G. C. Greubel_, Jul 02 2016 *)
%t A167954 coxG[{16, 666, -36, 40}] (* The coxG program is at A169452 *) (* _G. C. Greubel_, Sep 06 2023 *)
%o A167954 (Magma) R<x>:=PowerSeriesRing(Integers(), 40); Coefficients(R!( (1+x)*(1-x^16)/(1-37*x+702*x^16-666*x^17) )); // _G. C. Greubel_, Sep 06 2023
%o A167954 (SageMath)
%o A167954 def A167955_list(prec):
%o A167954 P.<x> = PowerSeriesRing(ZZ, prec)
%o A167954 return P( (1+x)*(1-x^16)/(1-37*x+702*x^16-666*x^17) ).list()
%o A167954 A167955_list(40) # _G. C. Greubel_, Sep 06 2023
%Y A167954 Cf. A154638, A169452, A170757.
%K A167954 nonn
%O A167954 0,2
%A A167954 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009