cp's OEIS Frontend

A170607 Number of reduced words of length n in Coxeter group on 22 generators S_i with relations (S_i)^2 = (S_i S_j)^48 = I.

%I A170607 #9 Nov 21 2016 12:10:00
%S A170607 1,22,462,9702,203742,4278582,89850222,1886854662,39623947902,
%T A170607 832102905942,17474161024782,366957381520422,7706105011928862,
%U A170607 161828205250506102,3398392310260628142,71366238515473190982
%N A170607 Number of reduced words of length n in Coxeter group on 22 generators S_i with relations (S_i)^2 = (S_i S_j)^48 = I.
%C A170607 The initial terms coincide with those of A170741, although the two sequences are eventually different.
%C A170607 Computed with MAGMA using commands similar to those used to compute A154638.
%H A170607 <a href="/index/Rec#order_48">Index entries for linear recurrences with constant coefficients</a>, signature (20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, -210).
%F A170607 G.f. (t^48 + 2*t^47 + 2*t^46 + 2*t^45 + 2*t^44 + 2*t^43 + 2*t^42 + 2*t^41 +
%F A170607 2*t^40 + 2*t^39 + 2*t^38 + 2*t^37 + 2*t^36 + 2*t^35 + 2*t^34 + 2*t^33 +
%F A170607 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 A170607 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 A170607 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 A170607 2*t^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t +
%F A170607 1)/(210*t^48 - 20*t^47 - 20*t^46 - 20*t^45 - 20*t^44 - 20*t^43 - 20*t^42
%F A170607 - 20*t^41 - 20*t^40 - 20*t^39 - 20*t^38 - 20*t^37 - 20*t^36 - 20*t^35 -
%F A170607 20*t^34 - 20*t^33 - 20*t^32 - 20*t^31 - 20*t^30 - 20*t^29 - 20*t^28 -
%F A170607 20*t^27 - 20*t^26 - 20*t^25 - 20*t^24 - 20*t^23 - 20*t^22 - 20*t^21 -
%F A170607 20*t^20 - 20*t^19 - 20*t^18 - 20*t^17 - 20*t^16 - 20*t^15 - 20*t^14 -
%F A170607 20*t^13 - 20*t^12 - 20*t^11 - 20*t^10 - 20*t^9 - 20*t^8 - 20*t^7 -
%F A170607 20*t^6 - 20*t^5 - 20*t^4 - 20*t^3 - 20*t^2 - 20*t + 1)
%t A170607 With[{num=Total[2t^Range[47]]+t^48+1,den=Total[-20 t^Range[47]]+210t^48+1}, CoefficientList[Series[num/den,{t,0,20}],t]] (* _Harvey P. Dale_, Mar 01 2012 *)
%K A170607 nonn
%O A170607 0,2
%A A170607 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009