cp's OEIS Frontend

A169486 Number of reduced words of length n in Coxeter group on 41 generators S_i with relations (S_i)^2 = (S_i S_j)^33 = I.

%I A169486 #8 Nov 26 2016 07:34:05
%S A169486 1,41,1640,65600,2624000,104960000,4198400000,167936000000,
%T A169486 6717440000000,268697600000000,10747904000000000,429916160000000000,
%U A169486 17196646400000000000,687865856000000000000,27514634240000000000000
%N A169486 Number of reduced words of length n in Coxeter group on 41 generators S_i with relations (S_i)^2 = (S_i S_j)^33 = I.
%C A169486 The initial terms coincide with those of A170760, although the two sequences are eventually different.
%C A169486 Computed with MAGMA using commands similar to those used to compute A154638.
%H A169486 <a href="/index/Rec#order_33">Index entries for linear recurrences with constant coefficients</a>, signature (39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, 39, -780).
%F A169486 G.f. (t^33 + 2*t^32 + 2*t^31 + 2*t^30 + 2*t^29 + 2*t^28 + 2*t^27 + 2*t^26 +
%F A169486 2*t^25 + 2*t^24 + 2*t^23 + 2*t^22 + 2*t^21 + 2*t^20 + 2*t^19 + 2*t^18 +
%F A169486 2*t^17 + 2*t^16 + 2*t^15 + 2*t^14 + 2*t^13 + 2*t^12 + 2*t^11 + 2*t^10 +
%F A169486 2*t^9 + 2*t^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t +
%F A169486 1)/(780*t^33 - 39*t^32 - 39*t^31 - 39*t^30 - 39*t^29 - 39*t^28 - 39*t^27
%F A169486 - 39*t^26 - 39*t^25 - 39*t^24 - 39*t^23 - 39*t^22 - 39*t^21 - 39*t^20 -
%F A169486 39*t^19 - 39*t^18 - 39*t^17 - 39*t^16 - 39*t^15 - 39*t^14 - 39*t^13 -
%F A169486 39*t^12 - 39*t^11 - 39*t^10 - 39*t^9 - 39*t^8 - 39*t^7 - 39*t^6 - 39*t^5
%F A169486 - 39*t^4 - 39*t^3 - 39*t^2 - 39*t + 1)
%t A169486 coxG[{33,780,-39}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Sep 27 2014 *)
%K A169486 nonn
%O A169486 0,2
%A A169486 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009