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 A164911 #6 Nov 23 2016 18:28:16 %S A164911 1,20,380,7220,137180,2606420,49521980,940917620,17877434590, %T A164911 339671253600,6453753750000,122621319950400,2329805054365200, %U A164911 44266295563783200,841059606797924400,15980132359795392000 %N A164911 Number of reduced words of length n in Coxeter group on 20 generators S_i with relations (S_i)^2 = (S_i S_j)^8 = I. %C A164911 The initial terms coincide with those of A170739, although the two sequences are eventually different. %C A164911 Computed with MAGMA using commands similar to those used to compute A154638. %H A164911 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (18, 18, 18, 18, 18, 18, 18, -171). %F A164911 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)/(171*t^8 - %F A164911 18*t^7 - 18*t^6 - 18*t^5 - 18*t^4 - 18*t^3 - 18*t^2 - 18*t + 1) %K A164911 nonn %O A164911 0,2 %A A164911 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009