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 A164909 #6 Nov 23 2016 18:28:00 %S A164909 1,19,342,6156,110808,1994544,35901792,646232256,11632180437, %T A164909 209379244788,3768826350951,67838873322924,1221099701917140, %U A164909 21979794312389664,395636291824874544,7121453148481232448 %N A164909 Number of reduced words of length n in Coxeter group on 19 generators S_i with relations (S_i)^2 = (S_i S_j)^8 = I. %C A164909 The initial terms coincide with those of A170738, although the two sequences are eventually different. %C A164909 Computed with MAGMA using commands similar to those used to compute A154638. %H A164909 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (17, 17, 17, 17, 17, 17, 17, -153). %F A164909 G.f. (t^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(153*t^8 - %F A164909 17*t^7 - 17*t^6 - 17*t^5 - 17*t^4 - 17*t^3 - 17*t^2 - 17*t + 1) %K A164909 nonn %O A164909 0,2 %A A164909 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009