cp's OEIS Frontend

A170230 Number of reduced words of length n in Coxeter group on 29 generators S_i with relations (S_i)^2 = (S_i S_j)^40 = I.

%I A170230 #8 Nov 22 2016 15:24:33
%S A170230 1,29,812,22736,636608,17825024,499100672,13974818816,391294926848,
%T A170230 10956257951744,306775222648832,8589706234167296,240511774556684288,
%U A170230 6734329687587160064,188561231252440481792,5279714475068333490176
%N A170230 Number of reduced words of length n in Coxeter group on 29 generators S_i with relations (S_i)^2 = (S_i S_j)^40 = I.
%C A170230 The initial terms coincide with those of A170748, although the two sequences are eventually different.
%C A170230 Computed with MAGMA using commands similar to those used to compute A154638.
%H A170230 <a href="/index/Rec#order_40">Index entries for linear recurrences with constant coefficients</a>, signature (27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, -378).
%F A170230 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 A170230 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 A170230 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 A170230 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 A170230 2*t^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t +
%F A170230 1)/(378*t^40 - 27*t^39 - 27*t^38 - 27*t^37 - 27*t^36 - 27*t^35 - 27*t^34
%F A170230 - 27*t^33 - 27*t^32 - 27*t^31 - 27*t^30 - 27*t^29 - 27*t^28 - 27*t^27 -
%F A170230 27*t^26 - 27*t^25 - 27*t^24 - 27*t^23 - 27*t^22 - 27*t^21 - 27*t^20 -
%F A170230 27*t^19 - 27*t^18 - 27*t^17 - 27*t^16 - 27*t^15 - 27*t^14 - 27*t^13 -
%F A170230 27*t^12 - 27*t^11 - 27*t^10 - 27*t^9 - 27*t^8 - 27*t^7 - 27*t^6 - 27*t^5
%F A170230 - 27*t^4 - 27*t^3 - 27*t^2 - 27*t + 1)
%t A170230 coxG[{40,378,-27}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Dec 21 2014 *)
%K A170230 nonn
%O A170230 0,2
%A A170230 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009