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 A168845 #10 Nov 24 2016 18:35:37
%S A168845 1,24,552,12696,292008,6716184,154472232,3552861336,81715810728,
%T A168845 1879463646744,43227663875112,994236269127576,22867434189934248,
%U A168845 525950986368487704,12096872686475217192,278228071788929995416
%N A168845 Number of reduced words of length n in Coxeter group on 24 generators S_i with relations (S_i)^2 = (S_i S_j)^20 = I.
%C A168845 The initial terms coincide with those of A170743, although the two sequences are eventually different.
%C A168845 First disagreement at index 20: a(20) = 1790771302262177053485803412, A170743(20) = 1790771302262177053485803688. - Klaus Brockhaus, Apr 02 2011
%C A168845 Computed with MAGMA using commands similar to those used to compute A154638.
%H A168845 <a href="/index/Rec#order_20">Index entries for linear recurrences with constant coefficients</a>, signature (22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, -253).
%F A168845 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)/(253*t^20 - 22*t^19 - 22*t^18 - 22*t^17 - 22*t^16 - 22*t^15 - 22*t^14 - 22*t^13 - 22*t^12 - 22*t^11 - 22*t^10 - 22*t^9 - 22*t^8 - 22*t^7 - 22*t^6 - 22*t^5 - 22*t^4 - 22*t^3 - 22*t^2 - 22*t + 1).
%t A168845 coxG[{20,253,-22}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Aug 31 2015 *)
%Y A168845 Cf. A170743 (G.f.: (1+x)/(1-23*x)).
%K A168845 nonn
%O A168845 0,2
%A A168845 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009