cp's OEIS Frontend

A169327 Number of reduced words of length n in Coxeter group on 26 generators S_i with relations (S_i)^2 = (S_i S_j)^30 = I.

%I A169327 #10 May 10 2018 00:22:41
%S A169327 1,26,650,16250,406250,10156250,253906250,6347656250,158691406250,
%T A169327 3967285156250,99182128906250,2479553222656250,61988830566406250,
%U A169327 1549720764160156250,38743019104003906250,968575477600097656250
%N A169327 Number of reduced words of length n in Coxeter group on 26 generators S_i with relations (S_i)^2 = (S_i S_j)^30 = I.
%C A169327 The initial terms coincide with those of A170745, although the two sequences are eventually different.
%C A169327 First disagreement at index 30: a(30) = 902056207507939689094200730323791503905925, A170745(30) = 902056207507939689094200730323791503906250. - _Klaus Brockhaus_, Jun 22 2011
%C A169327 Computed with Magma using commands similar to those used to compute A154638.
%H A169327 <a href="/index/Rec#order_30">Index entries for linear recurrences with constant coefficients</a>, signature (24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, -300).
%F A169327 G.f.: (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)/(300*t^30 - 24*t^29 - 24*t^28 - 24*t^27 - 24*t^26 - 24*t^25 - 24*t^24 - 24*t^23 - 24*t^22 - 24*t^21 - 24*t^20 - 24*t^19 - 24*t^18 - 24*t^17 - 24*t^16 - 24*t^15 - 24*t^14 - 24*t^13 - 24*t^12 - 24*t^11 - 24*t^10 - 24*t^9 - 24*t^8 - 24*t^7 - 24*t^6 - 24*t^5 - 24*t^4 - 24*t^3 - 24*t^2 - 24*t + 1).
%Y A169327 Cf. A170745 (G.f.: (1+x)/(1-25*x)).
%K A169327 nonn
%O A169327 0,2
%A A169327 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009