cp's OEIS Frontend

A170135 Number of reduced words of length n in Coxeter group on 30 generators S_i with relations (S_i)^2 = (S_i S_j)^38 = I.

%I A170135 #8 May 14 2017 17:36:45
%S A170135 1,30,870,25230,731670,21218430,615334470,17844699630,517496289270,
%T A170135 15007392388830,435214379276070,12621216999006030,366015292971174870,
%U A170135 10614443496164071230,307818861388758065670,8926746980273983904430
%N A170135 Number of reduced words of length n in Coxeter group on 30 generators S_i with relations (S_i)^2 = (S_i S_j)^38 = I.
%C A170135 The initial terms coincide with those of A170749, although the two sequences are eventually different.
%C A170135 Computed with MAGMA using commands similar to those used to compute A154638.
%H A170135 <a href="/index/Rec#order_38">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, 28, 28, -406).
%F A170135 G.f. (t^38 + 2*t^37 + 2*t^36 + 2*t^35 + 2*t^34 + 2*t^33 + 2*t^32 + 2*t^31 +
%F A170135 2*t^30 + 2*t^29 + 2*t^28 + 2*t^27 + 2*t^26 + 2*t^25 + 2*t^24 + 2*t^23 +
%F A170135 2*t^22 + 2*t^21 + 2*t^20 + 2*t^19 + 2*t^18 + 2*t^17 + 2*t^16 + 2*t^15 +
%F A170135 2*t^14 + 2*t^13 + 2*t^12 + 2*t^11 + 2*t^10 + 2*t^9 + 2*t^8 + 2*t^7 +
%F A170135 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(406*t^38 - 28*t^37 -
%F A170135 28*t^36 - 28*t^35 - 28*t^34 - 28*t^33 - 28*t^32 - 28*t^31 - 28*t^30 -
%F A170135 28*t^29 - 28*t^28 - 28*t^27 - 28*t^26 - 28*t^25 - 28*t^24 - 28*t^23 -
%F A170135 28*t^22 - 28*t^21 - 28*t^20 - 28*t^19 - 28*t^18 - 28*t^17 - 28*t^16 -
%F A170135 28*t^15 - 28*t^14 - 28*t^13 - 28*t^12 - 28*t^11 - 28*t^10 - 28*t^9 -
%F A170135 28*t^8 - 28*t^7 - 28*t^6 - 28*t^5 - 28*t^4 - 28*t^3 - 28*t^2 - 28*t + 1)
%t A170135 coxG[{38,406,-28}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Jun 19 2015 *)
%K A170135 nonn
%O A170135 0,2
%A A170135 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009