cp's OEIS Frontend

A170039 Number of reduced words of length n in Coxeter group on 30 generators S_i with relations (S_i)^2 = (S_i S_j)^36 = I.

%I A170039 #8 Nov 26 2016 09:45:22
%S A170039 1,30,870,25230,731670,21218430,615334470,17844699630,517496289270,
%T A170039 15007392388830,435214379276070,12621216999006030,366015292971174870,
%U A170039 10614443496164071230,307818861388758065670,8926746980273983904430
%N A170039 Number of reduced words of length n in Coxeter group on 30 generators S_i with relations (S_i)^2 = (S_i S_j)^36 = I.
%C A170039 The initial terms coincide with those of A170749, although the two sequences are eventually different.
%C A170039 Computed with MAGMA using commands similar to those used to compute A154638.
%H A170039 <a href="/index/Rec#order_36">Index entries for linear recurrences with constant coefficients</a>, signature (28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, -406).
%F A170039 G.f. (t^36 + 2*t^35 + 2*t^34 + 2*t^33 + 2*t^32 + 2*t^31 + 2*t^30 + 2*t^29 +
%F A170039 2*t^28 + 2*t^27 + 2*t^26 + 2*t^25 + 2*t^24 + 2*t^23 + 2*t^22 + 2*t^21 +
%F A170039 2*t^20 + 2*t^19 + 2*t^18 + 2*t^17 + 2*t^16 + 2*t^15 + 2*t^14 + 2*t^13 +
%F A170039 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
%F A170039 + 2*t^3 + 2*t^2 + 2*t + 1)/(406*t^36 - 28*t^35 - 28*t^34 - 28*t^33 -
%F A170039 28*t^32 - 28*t^31 - 28*t^30 - 28*t^29 - 28*t^28 - 28*t^27 - 28*t^26 -
%F A170039 28*t^25 - 28*t^24 - 28*t^23 - 28*t^22 - 28*t^21 - 28*t^20 - 28*t^19 -
%F A170039 28*t^18 - 28*t^17 - 28*t^16 - 28*t^15 - 28*t^14 - 28*t^13 - 28*t^12 -
%F A170039 28*t^11 - 28*t^10 - 28*t^9 - 28*t^8 - 28*t^7 - 28*t^6 - 28*t^5 - 28*t^4
%F A170039 - 28*t^3 - 28*t^2 - 28*t + 1)
%t A170039 coxG[{36,406,-28}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Aug 02 2015 *)
%K A170039 nonn
%O A170039 0,2
%A A170039 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009