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 A164636 #12 Feb 22 2024 14:30:27
%S A164636 1,23,506,11132,244904,5387888,118533536,2607737539,57370220292,
%T A164636 1262144724225,27767181244572,610877928236268,13439313120022944,
%U A164636 295664860014655824,6504626290553815116,143101764537275790477
%N A164636 Number of reduced words of length n in Coxeter group on 23 generators S_i with relations (S_i)^2 = (S_i S_j)^7 = I.
%C A164636 The initial terms coincide with those of A170742, although the two sequences are eventually different.
%C A164636 Computed with MAGMA using commands similar to those used to compute A154638.
%H A164636 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (21,21,21,21,21,21,-231).
%F A164636 G.f.: (t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(231*t^7 - 21*t^6 - 21*t^5 - 21*t^4 - 21*t^3 - 21*t^2 - 21*t + 1).
%t A164636 coxG[{7,231,-21}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Aug 26 2020 *)
%K A164636 nonn
%O A164636 0,2
%A A164636 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009