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 A168864 #10 Nov 24 2016 18:40:52
%S A168864 1,43,1806,75852,3185784,133802928,5619722976,236028364992,
%T A168864 9913191329664,416354035845888,17486869505527296,734448519232146432,
%U A168864 30846837807750150144,1295567187925506306048,54413821892871264854016
%N A168864 Number of reduced words of length n in Coxeter group on 43 generators S_i with relations (S_i)^2 = (S_i S_j)^20 = I.
%C A168864 The initial terms coincide with those of A170762, although the two sequences are eventually different.
%C A168864 First disagreement at index 20: a(20) = 298679195682332540089125349883001, A170762(20) = 298679195682332540089125349883904. - Klaus Brockhaus, Apr 04 2011
%C A168864 Computed with MAGMA using commands similar to those used to compute A154638.
%H A168864 <a href="/index/Rec#order_20">Index entries for linear recurrences with constant coefficients</a>, signature (41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, -861).
%F A168864 G.f.: (t^20 + 2*t^19 + 2*t^18 + 2*t^17 + 2*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)/(861*t^20 - 41*t^19 - 41*t^18 - 41*t^17 - 41*t^16 - 41*t^15 - 41*t^14 - 41*t^13 - 41*t^12 - 41*t^11 - 41*t^10 - 41*t^9 - 41*t^8 - 41*t^7 - 41*t^6 - 41*t^5 - 41*t^4 - 41*t^3 - 41*t^2 - 41*t + 1).
%t A168864 coxG[{20,861,-41}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Feb 19 2016 *)
%Y A168864 Cf. A170762 (G.f.: (1+x)/(1-42*x)).
%K A168864 nonn
%O A168864 0,2
%A A168864 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009