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 A162744 #7 Oct 02 2021 17:22:56
%S A162744 1,7,42,231,1260,6825,36960,200025,1082550,5858475,31704750,171577875,
%T A162744 928536000,5024998125,27194002500,147166963125,796429856250,
%U A162744 4310074059375,23325015131250,126228998109375,683118955312500
%N A162744 Number of reduced words of length n in Coxeter group on 7 generators S_i with relations (S_i)^2 = (S_i S_j)^3 = I.
%C A162744 The initial terms coincide with those of A003949, although the two sequences are eventually different.
%C A162744 Computed with MAGMA using commands similar to those used to compute A154638.
%H A162744 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (5, 5, -15).
%F A162744 G.f.: (t^3 + 2*t^2 + 2*t + 1)/(15*t^3 - 5*t^2 - 5*t + 1)
%t A162744 coxG[{3,15,-5}] (* The coxG program is at A169452 *) (* or *) LinearRecurrence[{5,5,-15},{1,7,42,231},30] (* _Harvey P. Dale_, Oct 02 2021 *)
%K A162744 nonn
%O A162744 0,2
%A A162744 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009