# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a168819 Showing 1-1 of 1 %I A168819 #15 Apr 11 2024 17:02:50 %S A168819 1,46,2070,93150,4191750,188628750,8488293750,381973218750, %T A168819 17188794843750,773495767968750,34807309558593750,1566328930136718750, %U A168819 70484801856152343750,3171816083526855468750,142731723758708496093750 %N A168819 Number of reduced words of length n in Coxeter group on 46 generators S_i with relations (S_i)^2 = (S_i S_j)^19 = I. %C A168819 The initial terms coincide with those of A170765, although the two sequences are eventually different. %C A168819 First disagreement at index 19: a(19) = 26338017363212431205749511717715, A170765(19) = 26338017363212431205749511718750. - _Klaus Brockhaus_, Apr 01 2011 %C A168819 Computed with MAGMA using commands similar to those used to compute A154638. %H A168819 G. C. Greubel, Table of n, a(n) for n = 0..500 %H A168819 Index entries for linear recurrences with constant coefficients, signature (44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, -990). %F A168819 G.f.: (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)/(990*t^19 - 44*t^18 - 44*t^17 - 44*t^16 - 44*t^15 - 44*t^14 - 44*t^13 - 44*t^12 - 44*t^11 - 44*t^10 - 44*t^9 - 44*t^8 - 44*t^7 - 44*t^6 - 44*t^5 - 44*t^4 - 44*t^3 - 44*t^2 - 44*t + 1). %t A168819 CoefficientList[Series[(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)/(990*t^19 - 44*t^18 - 44*t^17 - 44*t^16 - 44*t^15 - 44*t^14 - 44*t^13 - 44*t^12 - 44*t^11 - 44*t^10 - 44*t^9 - 44*t^8 - 44*t^7 - 44*t^6 - 44*t^5 - 44*t^4 - 44*t^3 - 44*t^2 - 44*t + 1), {t,0,50}], t] (* _G. C. Greubel_, Nov 21 2016 *) %t A168819 coxG[{19,990,-44}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Apr 11 2024 *) %Y A168819 Cf. A170765 (G.f.: (1+x)/(1-45*x)). %K A168819 nonn,easy %O A168819 0,2 %A A168819 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE