# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a168866 Showing 1-1 of 1 %I A168866 #10 Sep 17 2020 12:23:43 %S A168866 1,45,1980,87120,3833280,168664320,7421230080,326534123520, %T A168866 14367501434880,632170063134720,27815482777927680,1223881242228817920, %U A168866 53850774658067988480,2369434084954991493120,104255099738019625697280 %N A168866 Number of reduced words of length n in Coxeter group on 45 generators S_i with relations (S_i)^2 = (S_i S_j)^20 = I. %C A168866 The initial terms coincide with those of A170764, although the two sequences are eventually different. %C A168866 First disagreement at index 20: a(20) = 756507724787653779947106525510690, A170764(20) = 756507724787653779947106525511680. - Klaus Brockhaus, Apr 04 2011 %C A168866 Computed with MAGMA using commands similar to those used to compute A154638. %H A168866 Index entries for linear recurrences with constant coefficients, signature (43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, -946). %F A168866 G.f.: (t^20 + 2*t^19 + 2*t^18 + 2*t^17 + 2*t^16 + 2*t^15 + 2*t^14 + 2*t^13 + 2*t^12 + 2*t^11 + 2*t^10 + 2*t^9 + 2*t^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(946*t^20 - 43*t^19 - 43*t^18 - 43*t^17 - 43*t^16 - 43*t^15 - 43*t^14 - 43*t^13 - 43*t^12 - 43*t^11 - 43*t^10 - 43*t^9 - 43*t^8 - 43*t^7 - 43*t^6 - 43*t^5 - 43*t^4 - 43*t^3 - 43*t^2 - 43*t + 1). %t A168866 coxG[{20,946,-43}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Sep 17 2020 *) %Y A168866 Cf. A170764 (G.f.: (1+x)/(1-44*x)). %K A168866 nonn %O A168866 0,2 %A A168866 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE