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 A164665 #12 Feb 22 2024 20:31:44
%S A164665 1,29,812,22736,636608,17825024,499100672,13974818410,391294904112,
%T A164665 10956256997238,306775187021520,8589704987370528,240511732667877888,
%U A164665 6734328319302667776,188561187469333295694,5279713095949377473052
%N A164665 Number of reduced words of length n in Coxeter group on 29 generators S_i with relations (S_i)^2 = (S_i S_j)^7 = I.
%C A164665 The initial terms coincide with those of A170748, although the two sequences are eventually different.
%C A164665 Computed with MAGMA using commands similar to those used to compute A154638.
%H A164665 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (27,27,27,27,27,27,-378).
%F A164665 G.f.: (t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(378*t^7 - 27*t^6 - 27*t^5 - 27*t^4 - 27*t^3 - 27*t^2 - 27*t + 1).
%t A164665 coxG[{7,378,-27}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Aug 19 2019 *)
%K A164665 nonn
%O A164665 0,2
%A A164665 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009