cp's OEIS Frontend

A170218 Number of reduced words of length n in Coxeter group on 17 generators S_i with relations (S_i)^2 = (S_i S_j)^40 = I.

%I A170218 #6 Nov 22 2016 15:18:24
%S A170218 1,17,272,4352,69632,1114112,17825792,285212672,4563402752,
%T A170218 73014444032,1168231104512,18691697672192,299067162755072,
%U A170218 4785074604081152,76561193665298432,1224979098644774912,19599665578316398592
%N A170218 Number of reduced words of length n in Coxeter group on 17 generators S_i with relations (S_i)^2 = (S_i S_j)^40 = I.
%C A170218 The initial terms coincide with those of A170736, although the two sequences are eventually different.
%C A170218 Computed with MAGMA using commands similar to those used to compute A154638.
%H A170218 <a href="/index/Rec#order_40">Index entries for linear recurrences with constant coefficients</a>, signature (15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, -120).
%F A170218 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 A170218 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 A170218 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 A170218 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 A170218 2*t^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t +
%F A170218 1)/(120*t^40 - 15*t^39 - 15*t^38 - 15*t^37 - 15*t^36 - 15*t^35 - 15*t^34
%F A170218 - 15*t^33 - 15*t^32 - 15*t^31 - 15*t^30 - 15*t^29 - 15*t^28 - 15*t^27 -
%F A170218 15*t^26 - 15*t^25 - 15*t^24 - 15*t^23 - 15*t^22 - 15*t^21 - 15*t^20 -
%F A170218 15*t^19 - 15*t^18 - 15*t^17 - 15*t^16 - 15*t^15 - 15*t^14 - 15*t^13 -
%F A170218 15*t^12 - 15*t^11 - 15*t^10 - 15*t^9 - 15*t^8 - 15*t^7 - 15*t^6 - 15*t^5
%F A170218 - 15*t^4 - 15*t^3 - 15*t^2 - 15*t + 1)
%K A170218 nonn
%O A170218 0,2
%A A170218 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009