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 A163091 #9 Mar 23 2020 06:48:28
%S A163091 1,15,210,2940,41055,573300,8005725,111793500,1561106820,21799608285,
%T A163091 304414090890,4250899269435,59360407871310,828920611657320,
%U A163091 11575213262103855,161638593827703720,2257153663002754425,31519345335542489880,440142444293996873520,6146237150764726493205
%N A163091 Number of reduced words of length n in Coxeter group on 15 generators S_i with relations (S_i)^2 = (S_i S_j)^4 = I.
%C A163091 The initial terms coincide with those of A170734, although the two sequences are eventually different.
%C A163091 Computed with MAGMA using commands similar to those used to compute A154638.
%H A163091 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (13,13,13,-91).
%F A163091 G.f.: (t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(91*t^4 - 13*t^3 - 13*t^2 - 13*t + 1).
%t A163091 CoefficientList[Series[(t^4 + 2 t^3 + 2 t^2 + 2 t + 1)/(91 t^4 - 13 t^3 - 13 t^2 - 13 t + 1), {t, 0, 20}], t] (* _Jinyuan Wang_, Mar 22 2020 *)
%Y A163091 Cf. A170734.
%K A163091 nonn
%O A163091 0,2
%A A163091 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009
%E A163091 More terms from _Jinyuan Wang_, Mar 22 2020