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 A164742 #12 Dec 19 2024 12:06:53
%S A164742 1,7,42,252,1512,9072,54432,326592,1959531,11757060,70541625,
%T A164742 423245340,2539445580,15236514720,91418135760,548503099200,
%U A164742 3290984303460,19745700072525,118472965958550,710830388968875,4264937893581750
%N A164742 Number of reduced words of length n in Coxeter group on 7 generators S_i with relations (S_i)^2 = (S_i S_j)^8 = I.
%C A164742 The initial terms coincide with those of A003949, although the two sequences are eventually different.
%C A164742 Computed with MAGMA using commands similar to those used to compute A154638.
%H A164742 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (5, 5, 5, 5, 5, 5, 5, -15).
%F A164742 G.f.: (t^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(15*t^8 - 5*t^7 - 5*t^6 - 5*t^5 - 5*t^4 - 5*t^3 - 5*t^2 - 5*t + 1).
%t A164742 coxG[{8,15,-5}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Dec 19 2024 *)
%K A164742 nonn
%O A164742 0,2
%A A164742 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009