cp's OEIS Frontend

A169562 Number of reduced words of length n in Coxeter group on 21 generators S_i with relations (S_i)^2 = (S_i S_j)^35 = I.

%I A169562 #6 Nov 26 2016 09:29:00
%S A169562 1,21,420,8400,168000,3360000,67200000,1344000000,26880000000,
%T A169562 537600000000,10752000000000,215040000000000,4300800000000000,
%U A169562 86016000000000000,1720320000000000000,34406400000000000000
%N A169562 Number of reduced words of length n in Coxeter group on 21 generators S_i with relations (S_i)^2 = (S_i S_j)^35 = I.
%C A169562 The initial terms coincide with those of A170740, although the two sequences are eventually different.
%C A169562 Computed with MAGMA using commands similar to those used to compute A154638.
%H A169562 <a href="/index/Rec#order_35">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, 19, 19, -190).
%F A169562 G.f. (t^35 + 2*t^34 + 2*t^33 + 2*t^32 + 2*t^31 + 2*t^30 + 2*t^29 + 2*t^28 +
%F A169562 2*t^27 + 2*t^26 + 2*t^25 + 2*t^24 + 2*t^23 + 2*t^22 + 2*t^21 + 2*t^20 +
%F A169562 2*t^19 + 2*t^18 + 2*t^17 + 2*t^16 + 2*t^15 + 2*t^14 + 2*t^13 + 2*t^12 +
%F A169562 2*t^11 + 2*t^10 + 2*t^9 + 2*t^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3
%F A169562 + 2*t^2 + 2*t + 1)/(190*t^35 - 19*t^34 - 19*t^33 - 19*t^32 - 19*t^31 -
%F A169562 19*t^30 - 19*t^29 - 19*t^28 - 19*t^27 - 19*t^26 - 19*t^25 - 19*t^24 -
%F A169562 19*t^23 - 19*t^22 - 19*t^21 - 19*t^20 - 19*t^19 - 19*t^18 - 19*t^17 -
%F A169562 19*t^16 - 19*t^15 - 19*t^14 - 19*t^13 - 19*t^12 - 19*t^11 - 19*t^10 -
%F A169562 19*t^9 - 19*t^8 - 19*t^7 - 19*t^6 - 19*t^5 - 19*t^4 - 19*t^3 - 19*t^2 -
%F A169562 19*t + 1)
%K A169562 nonn
%O A169562 0,2
%A A169562 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009