cp's OEIS Frontend

A170029 Number of reduced words of length n in Coxeter group on 20 generators S_i with relations (S_i)^2 = (S_i S_j)^36 = I.

%I A170029 #6 Nov 26 2016 09:42:38
%S A170029 1,20,380,7220,137180,2606420,49521980,940917620,17877434780,
%T A170029 339671260820,6453753955580,122621325156020,2329805177964380,
%U A170029 44266298381323220,841059669245141180,15980133715657682420
%N A170029 Number of reduced words of length n in Coxeter group on 20 generators S_i with relations (S_i)^2 = (S_i S_j)^36 = I.
%C A170029 The initial terms coincide with those of A170739, although the two sequences are eventually different.
%C A170029 Computed with MAGMA using commands similar to those used to compute A154638.
%H A170029 <a href="/index/Rec#order_36">Index entries for linear recurrences with constant coefficients</a>, signature (18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, -171).
%F A170029 G.f. (t^36 + 2*t^35 + 2*t^34 + 2*t^33 + 2*t^32 + 2*t^31 + 2*t^30 + 2*t^29 +
%F A170029 2*t^28 + 2*t^27 + 2*t^26 + 2*t^25 + 2*t^24 + 2*t^23 + 2*t^22 + 2*t^21 +
%F A170029 2*t^20 + 2*t^19 + 2*t^18 + 2*t^17 + 2*t^16 + 2*t^15 + 2*t^14 + 2*t^13 +
%F A170029 2*t^12 + 2*t^11 + 2*t^10 + 2*t^9 + 2*t^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4
%F A170029 + 2*t^3 + 2*t^2 + 2*t + 1)/(171*t^36 - 18*t^35 - 18*t^34 - 18*t^33 -
%F A170029 18*t^32 - 18*t^31 - 18*t^30 - 18*t^29 - 18*t^28 - 18*t^27 - 18*t^26 -
%F A170029 18*t^25 - 18*t^24 - 18*t^23 - 18*t^22 - 18*t^21 - 18*t^20 - 18*t^19 -
%F A170029 18*t^18 - 18*t^17 - 18*t^16 - 18*t^15 - 18*t^14 - 18*t^13 - 18*t^12 -
%F A170029 18*t^11 - 18*t^10 - 18*t^9 - 18*t^8 - 18*t^7 - 18*t^6 - 18*t^5 - 18*t^4
%F A170029 - 18*t^3 - 18*t^2 - 18*t + 1)
%K A170029 nonn
%O A170029 0,2
%A A170029 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009