cp's OEIS Frontend

A169466 Number of reduced words of length n in Coxeter group on 21 generators S_i with relations (S_i)^2 = (S_i S_j)^33 = I.

%I A169466 #6 Nov 26 2016 07:21:29
%S A169466 1,21,420,8400,168000,3360000,67200000,1344000000,26880000000,
%T A169466 537600000000,10752000000000,215040000000000,4300800000000000,
%U A169466 86016000000000000,1720320000000000000,34406400000000000000
%N A169466 Number of reduced words of length n in Coxeter group on 21 generators S_i with relations (S_i)^2 = (S_i S_j)^33 = I.
%C A169466 The initial terms coincide with those of A170740, although the two sequences are eventually different.
%C A169466 Computed with MAGMA using commands similar to those used to compute A154638.
%H A169466 <a href="/index/Rec#order_33">Index entries for linear recurrences with constant coefficients</a>, signature (19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, -190).
%F A169466 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 A169466 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 A169466 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 A169466 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 A169466 1)/(190*t^33 - 19*t^32 - 19*t^31 - 19*t^30 - 19*t^29 - 19*t^28 - 19*t^27
%F A169466 - 19*t^26 - 19*t^25 - 19*t^24 - 19*t^23 - 19*t^22 - 19*t^21 - 19*t^20 -
%F A169466 19*t^19 - 19*t^18 - 19*t^17 - 19*t^16 - 19*t^15 - 19*t^14 - 19*t^13 -
%F A169466 19*t^12 - 19*t^11 - 19*t^10 - 19*t^9 - 19*t^8 - 19*t^7 - 19*t^6 - 19*t^5
%F A169466 - 19*t^4 - 19*t^3 - 19*t^2 - 19*t + 1)
%K A169466 nonn
%O A169466 0,2
%A A169466 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009