cp's OEIS Frontend

A170240 Number of reduced words of length n in Coxeter group on 39 generators S_i with relations (S_i)^2 = (S_i S_j)^40 = I.

%I A170240 #6 Nov 22 2016 15:29:51
%S A170240 1,39,1482,56316,2140008,81320304,3090171552,117426518976,
%T A170240 4462207721088,169563893401344,6443427949251072,244850262071540736,
%U A170240 9304309958718547968,353563778431304822784,13435423580389583265792
%N A170240 Number of reduced words of length n in Coxeter group on 39 generators S_i with relations (S_i)^2 = (S_i S_j)^40 = I.
%C A170240 The initial terms coincide with those of A170758, although the two sequences are eventually different.
%C A170240 Computed with MAGMA using commands similar to those used to compute A154638.
%H A170240 <a href="/index/Rec#order_40">Index entries for linear recurrences with constant coefficients</a>, signature (37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, -703).
%F A170240 G.f. (t^40 + 2*t^39 + 2*t^38 + 2*t^37 + 2*t^36 + 2*t^35 + 2*t^34 + 2*t^33 +
%F A170240 2*t^32 + 2*t^31 + 2*t^30 + 2*t^29 + 2*t^28 + 2*t^27 + 2*t^26 + 2*t^25 +
%F A170240 2*t^24 + 2*t^23 + 2*t^22 + 2*t^21 + 2*t^20 + 2*t^19 + 2*t^18 + 2*t^17 +
%F A170240 2*t^16 + 2*t^15 + 2*t^14 + 2*t^13 + 2*t^12 + 2*t^11 + 2*t^10 + 2*t^9 +
%F A170240 2*t^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t +
%F A170240 1)/(703*t^40 - 37*t^39 - 37*t^38 - 37*t^37 - 37*t^36 - 37*t^35 - 37*t^34
%F A170240 - 37*t^33 - 37*t^32 - 37*t^31 - 37*t^30 - 37*t^29 - 37*t^28 - 37*t^27 -
%F A170240 37*t^26 - 37*t^25 - 37*t^24 - 37*t^23 - 37*t^22 - 37*t^21 - 37*t^20 -
%F A170240 37*t^19 - 37*t^18 - 37*t^17 - 37*t^16 - 37*t^15 - 37*t^14 - 37*t^13 -
%F A170240 37*t^12 - 37*t^11 - 37*t^10 - 37*t^9 - 37*t^8 - 37*t^7 - 37*t^6 - 37*t^5
%F A170240 - 37*t^4 - 37*t^3 - 37*t^2 - 37*t + 1)
%K A170240 nonn
%O A170240 0,2
%A A170240 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009