cp's OEIS Frontend

A170249 Number of reduced words of length n in Coxeter group on 48 generators S_i with relations (S_i)^2 = (S_i S_j)^40 = I.

%I A170249 #9 Nov 22 2016 15:34:28
%S A170249 1,48,2256,106032,4983504,234224688,11008560336,517402335792,
%T A170249 24317909782224,1142941759764528,53718262708932816,
%U A170249 2524758347319842352,118663642324032590544,5577191189229531755568,262127985893787992511696
%N A170249 Number of reduced words of length n in Coxeter group on 48 generators S_i with relations (S_i)^2 = (S_i S_j)^40 = I.
%C A170249 The initial terms coincide with those of A170767, although the two sequences are eventually different.
%C A170249 Computed with MAGMA using commands similar to those used to compute A154638.
%H A170249 <a href="/index/Rec#order_40">Index entries for linear recurrences with constant coefficients</a>, signature (46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, -1081).
%F A170249 G.f. (t^40 + 2*t^39 + 2*t^38 + 2*t^37 + 2*t^36 + 2*t^35 + 2*t^34 + 2*t^33 +
%F A170249 2*t^32 + 2*t^31 + 2*t^30 + 2*t^29 + 2*t^28 + 2*t^27 + 2*t^26 + 2*t^25 +
%F A170249 2*t^24 + 2*t^23 + 2*t^22 + 2*t^21 + 2*t^20 + 2*t^19 + 2*t^18 + 2*t^17 +
%F A170249 2*t^16 + 2*t^15 + 2*t^14 + 2*t^13 + 2*t^12 + 2*t^11 + 2*t^10 + 2*t^9 +
%F A170249 2*t^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t +
%F A170249 1)/(1081*t^40 - 46*t^39 - 46*t^38 - 46*t^37 - 46*t^36 - 46*t^35 -
%F A170249 46*t^34 - 46*t^33 - 46*t^32 - 46*t^31 - 46*t^30 - 46*t^29 - 46*t^28 -
%F A170249 46*t^27 - 46*t^26 - 46*t^25 - 46*t^24 - 46*t^23 - 46*t^22 - 46*t^21 -
%F A170249 46*t^20 - 46*t^19 - 46*t^18 - 46*t^17 - 46*t^16 - 46*t^15 - 46*t^14 -
%F A170249 46*t^13 - 46*t^12 - 46*t^11 - 46*t^10 - 46*t^9 - 46*t^8 - 46*t^7 -
%F A170249 46*t^6 - 46*t^5 - 46*t^4 - 46*t^3 - 46*t^2 - 46*t + 1)
%t A170249 With[{num=Total[2t^Range[39]]+t^40+1,den=Total[-46 t^Range[39]]+ 1081t^40+ 1},CoefficientList[Series[num/den,{t,0,30}],t]] (* _Harvey P. Dale_, Aug 16 2011 *)
%K A170249 nonn
%O A170249 0,2
%A A170249 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009