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 A164684 #12 Feb 22 2024 15:30:29
%S A164684 1,40,1560,60840,2372760,92537640,3608967960,140749749660,
%T A164684 5489240206320,214080366860880,8349134261335920,325616234388803280,
%U A164684 12699033070834721520,495262287019738489680,19315229086799991370740
%N A164684 Number of reduced words of length n in Coxeter group on 40 generators S_i with relations (S_i)^2 = (S_i S_j)^7 = I.
%C A164684 The initial terms coincide with those of A170759, although the two sequences are eventually different.
%C A164684 Computed with MAGMA using commands similar to those used to compute A154638.
%H A164684 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (38,38,38,38,38,38,-741).
%F A164684 G.f.: (t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(741*t^7 - 38*t^6 - 38*t^5 - 38*t^4 - 38*t^3 - 38*t^2 - 38*t + 1).
%t A164684 coxG[{7,741,-38}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Aug 29 2021 *)
%K A164684 nonn
%O A164684 0,2
%A A164684 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009