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 A163104 #9 Mar 23 2020 06:48:08 %S A163104 1,18,306,5202,88281,1498176,25424928,431474688,7322358456, %T A163104 124264377216,2108833575552,35788044422016,607342437246528, %U A163104 10306929088604160,174914151758088192,2968387598501627904,50375140298107596288,854893330417826832384,14508001408391876911104 %N A163104 Number of reduced words of length n in Coxeter group on 18 generators S_i with relations (S_i)^2 = (S_i S_j)^4 = I. %C A163104 The initial terms coincide with those of A170737, although the two sequences are eventually different. %C A163104 Computed with MAGMA using commands similar to those used to compute A154638. %H A163104 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (16,16,16,-136). %F A163104 G.f.: (t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(136*t^4 - 16*t^3 - 16*t^2 - 16*t + 1). %o A163104 (PARI) Vec((t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(136*t^4 - 16*t^3 - 16*t^2 - 16*t + 1) + O(t^20)) \\ _Jinyuan Wang_, Mar 23 2020 %K A163104 nonn %O A163104 0,2 %A A163104 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009 %E A163104 More terms from _Jinyuan Wang_, Mar 23 2020