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 A163175 #11 Aug 16 2023 20:40:26
%S A163175 1,25,600,14400,345300,8280000,198547500,4761000000,114164729700,
%T A163175 2737573095600,65644673871900,1574103433035600,37745661174674100,
%U A163175 905108843301991200,21703740051934476300,520437222249938431200
%N A163175 Number of reduced words of length n in Coxeter group on 25 generators S_i with relations (S_i)^2 = (S_i S_j)^4 = I.
%C A163175 The initial terms coincide with those of A170744, although the two sequences are eventually different.
%C A163175 Computed with MAGMA using commands similar to those used to compute A154638.
%H A163175 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (23,23,23,-276).
%F A163175 G.f.: (t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(276*t^4 - 23*t^3 - 23*t^2 - 23*t + 1).
%t A163175 CoefficientList[Series[(t^4 + 2 t^3 + 2 t^2 + 2 t + 1)/(276 t^4 - 23 t^3 - 23 t^2 - 23 t + 1), {t, 0, 20}], t] (* _Jinyuan Wang_, Mar 23 2020 *)
%t A163175 coxG[{4,276,-23}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Aug 16 2023 *)
%K A163175 nonn
%O A163175 0,2
%A A163175 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009