cp's OEIS Frontend

A169515 Number of reduced words of length n in Coxeter group on 22 generators S_i with relations (S_i)^2 = (S_i S_j)^34 = I.

%I A169515 #8 Nov 26 2016 07:35:43
%S A169515 1,22,462,9702,203742,4278582,89850222,1886854662,39623947902,
%T A169515 832102905942,17474161024782,366957381520422,7706105011928862,
%U A169515 161828205250506102,3398392310260628142,71366238515473190982
%N A169515 Number of reduced words of length n in Coxeter group on 22 generators S_i with relations (S_i)^2 = (S_i S_j)^34 = I.
%C A169515 The initial terms coincide with those of A170741, although the two sequences are eventually different.
%C A169515 Computed with MAGMA using commands similar to those used to compute A154638.
%H A169515 <a href="/index/Rec#order_34">Index entries for linear recurrences with constant coefficients</a>, signature (20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, -210).
%F A169515 G.f. (t^34 + 2*t^33 + 2*t^32 + 2*t^31 + 2*t^30 + 2*t^29 + 2*t^28 + 2*t^27 +
%F A169515 2*t^26 + 2*t^25 + 2*t^24 + 2*t^23 + 2*t^22 + 2*t^21 + 2*t^20 + 2*t^19 +
%F A169515 2*t^18 + 2*t^17 + 2*t^16 + 2*t^15 + 2*t^14 + 2*t^13 + 2*t^12 + 2*t^11 +
%F A169515 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 +
%F A169515 2*t + 1)/(210*t^34 - 20*t^33 - 20*t^32 - 20*t^31 - 20*t^30 - 20*t^29 -
%F A169515 20*t^28 - 20*t^27 - 20*t^26 - 20*t^25 - 20*t^24 - 20*t^23 - 20*t^22 -
%F A169515 20*t^21 - 20*t^20 - 20*t^19 - 20*t^18 - 20*t^17 - 20*t^16 - 20*t^15 -
%F A169515 20*t^14 - 20*t^13 - 20*t^12 - 20*t^11 - 20*t^10 - 20*t^9 - 20*t^8 -
%F A169515 20*t^7 - 20*t^6 - 20*t^5 - 20*t^4 - 20*t^3 - 20*t^2 - 20*t + 1)
%t A169515 coxG[{34,210,-20}] (* The coxG program is at A169452 *) (* _Harvey P. Dale_, Jan 02 2015 *)
%K A169515 nonn
%O A169515 0,2
%A A169515 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009