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 A164633 #9 Feb 22 2024 13:33:20 %S A164633 1,20,380,7220,137180,2606420,49521980,940917430,17877427560, %T A164633 339671055240,6453748749960,122621201556840,2329802360424360, %U A164633 44266235934106440,841058313382886670,15980104736337918420 %N A164633 Number of reduced words of length n in Coxeter group on 20 generators S_i with relations (S_i)^2 = (S_i S_j)^7 = I. %C A164633 The initial terms coincide with those of A170739, although the two sequences are eventually different. %C A164633 Computed with MAGMA using commands similar to those used to compute A154638. %H A164633 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (18,18,18,18,18,18,-171). %F A164633 G.f.: (t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(171*t^7 - 18*t^6 - 18*t^5 - 18*t^4 - 18*t^3 - 18*t^2 - 18*t + 1). %K A164633 nonn %O A164633 0,2 %A A164633 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009