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 A165348 #8 May 06 2018 15:50:48
%S A165348 1,20,380,7220,137180,2606420,49521980,940917620,17877434780,
%T A165348 339671260630,6453753948360,122621324950440,2329805172758760,
%U A165348 44266298257724040,841059666427601160,15980133653210465640
%N A165348 Number of reduced words of length n in Coxeter group on 20 generators S_i with relations (S_i)^2 = (S_i S_j)^9 = I.
%C A165348 The initial terms coincide with those of A170739, although the two sequences are eventually different.
%C A165348 Computed with MAGMA using commands similar to those used to compute A154638.
%H A165348 <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (18, 18, 18, 18, 18, 18, 18, 18, -171).
%F A165348 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 A165348 1)/(171*t^9 - 18*t^8 - 18*t^7 - 18*t^6 - 18*t^5 - 18*t^4 - 18*t^3 -
%F A165348 18*t^2 - 18*t + 1)
%t A165348 coxG[{9,171,-18}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, May 06 2018 *)
%K A165348 nonn
%O A165348 0,2
%A A165348 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009