cp's OEIS Frontend

A169362 Number of reduced words of length n in Coxeter group on 13 generators S_i with relations (S_i)^2 = (S_i S_j)^31 = I.

%I A169362 #11 May 08 2018 01:12:22
%S A169362 1,13,156,1872,22464,269568,3234816,38817792,465813504,5589762048,
%T A169362 67077144576,804925734912,9659108818944,115909305827328,
%U A169362 1390911669927936,16690940039135232,200291280469622784
%N A169362 Number of reduced words of length n in Coxeter group on 13 generators S_i with relations (S_i)^2 = (S_i S_j)^31 = I.
%C A169362 The initial terms coincide with those of A170732, although the two sequences are eventually different.
%C A169362 First disagreement at index 31: a(31) = 3085892079397007482276353788608434, A170732(31) = 3085892079397007482276353788608512. - _Klaus Brockhaus_, Jun 17 2011
%C A169362 Computed with Magma using commands similar to those used to compute A154638.
%H A169362 <a href="/index/Rec#order_31">Index entries for linear recurrences with constant coefficients</a>, signature (11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, -66).
%F A169362 G.f.: (t^31 + 2*t^30 + 2*t^29 + 2*t^28 + 2*t^27 + 2*t^26 + 2*t^25 + 2*t^24 + 2*t^23 + 2*t^22 + 2*t^21 + 2*t^20 + 2*t^19 + 2*t^18 + 2*t^17 + 2*t^16 + 2*t^15 + 2*t^14 + 2*t^13 + 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 + 2*t^3 + 2*t^2 + 2*t + 1)/(66*t^31 - 11*t^30 - 11*t^29 - 11*t^28 - 11*t^27 - 11*t^26 - 11*t^25 - 11*t^24 - 11*t^23 - 11*t^22 - 11*t^21 - 11*t^20 - 11*t^19 - 11*t^18 - 11*t^17 - 11*t^16 - 11*t^15 - 11*t^14 - 11*t^13 - 11*t^12 - 11*t^11 - 11*t^10 - 11*t^9 - 11*t^8 - 11*t^7 - 11*t^6 - 11*t^5 - 11*t^4 - 11*t^3 - 11*t^2 - 11*t + 1).
%Y A169362 Cf. A170732 (G.f.: (1+x)/(1-12*x)).
%K A169362 nonn
%O A169362 0,2
%A A169362 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009