cp's OEIS Frontend

A170646 Number of reduced words of length n in Coxeter group on 13 generators S_i with relations (S_i)^2 = (S_i S_j)^49 = I.

%I A170646 #6 Nov 21 2016 11:16:53
%S A170646 1,13,156,1872,22464,269568,3234816,38817792,465813504,5589762048,
%T A170646 67077144576,804925734912,9659108818944,115909305827328,
%U A170646 1390911669927936,16690940039135232,200291280469622784
%N A170646 Number of reduced words of length n in Coxeter group on 13 generators S_i with relations (S_i)^2 = (S_i S_j)^49 = I.
%C A170646 The initial terms coincide with those of A170732, although the two sequences are eventually different.
%C A170646 Computed with MAGMA using commands similar to those used to compute A154638.
%H A170646 <a href="/index/Rec#order_49">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, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, -66).
%F A170646 G.f. (t^49 + 2*t^48 + 2*t^47 + 2*t^46 + 2*t^45 + 2*t^44 + 2*t^43 + 2*t^42 +
%F A170646 2*t^41 + 2*t^40 + 2*t^39 + 2*t^38 + 2*t^37 + 2*t^36 + 2*t^35 + 2*t^34 +
%F A170646 2*t^33 + 2*t^32 + 2*t^31 + 2*t^30 + 2*t^29 + 2*t^28 + 2*t^27 + 2*t^26 +
%F A170646 2*t^25 + 2*t^24 + 2*t^23 + 2*t^22 + 2*t^21 + 2*t^20 + 2*t^19 + 2*t^18 +
%F A170646 2*t^17 + 2*t^16 + 2*t^15 + 2*t^14 + 2*t^13 + 2*t^12 + 2*t^11 + 2*t^10 +
%F A170646 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 +
%F A170646 1)/(66*t^49 - 11*t^48 - 11*t^47 - 11*t^46 - 11*t^45 - 11*t^44 - 11*t^43
%F A170646 - 11*t^42 - 11*t^41 - 11*t^40 - 11*t^39 - 11*t^38 - 11*t^37 - 11*t^36 -
%F A170646 11*t^35 - 11*t^34 - 11*t^33 - 11*t^32 - 11*t^31 - 11*t^30 - 11*t^29 -
%F A170646 11*t^28 - 11*t^27 - 11*t^26 - 11*t^25 - 11*t^24 - 11*t^23 - 11*t^22 -
%F A170646 11*t^21 - 11*t^20 - 11*t^19 - 11*t^18 - 11*t^17 - 11*t^16 - 11*t^15 -
%F A170646 11*t^14 - 11*t^13 - 11*t^12 - 11*t^11 - 11*t^10 - 11*t^9 - 11*t^8 -
%F A170646 11*t^7 - 11*t^6 - 11*t^5 - 11*t^4 - 11*t^3 - 11*t^2 - 11*t + 1)
%K A170646 nonn
%O A170646 0,2
%A A170646 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009