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 A165358 #8 Aug 09 2020 12:53:12
%S A165358 1,21,420,8400,168000,3360000,67200000,1344000000,26880000000,
%T A165358 537599999790,10751999991600,215039999748210,4300799993288400,
%U A165358 86015999832252000,1720319995974720000,34406399906088000000
%N A165358 Number of reduced words of length n in Coxeter group on 21 generators S_i with relations (S_i)^2 = (S_i S_j)^9 = I.
%C A165358 The initial terms coincide with those of A170740, although the two sequences are eventually different.
%C A165358 Computed with MAGMA using commands similar to those used to compute A154638.
%H A165358 <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (19, 19, 19, 19, 19, 19, 19, 19, -190).
%F A165358 G.f. (t^9 + 2*t^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t +
%F A165358 1)/(190*t^9 - 19*t^8 - 19*t^7 - 19*t^6 - 19*t^5 - 19*t^4 - 19*t^3 -
%F A165358 19*t^2 - 19*t + 1)
%t A165358 coxG[{9,190,-19}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Aug 09 2020 *)
%K A165358 nonn
%O A165358 0,2
%A A165358 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009