This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A167693 #10 Nov 24 2016 11:07:17 %S A167693 1,22,462,9702,203742,4278582,89850222,1886854662,39623947902, %T A167693 832102905942,17474161024782,366957381520422,7706105011928862, %U A167693 161828205250506102,3398392310260628142,71366238515473190751 %N A167693 Number of reduced words of length n in Coxeter group on 22 generators S_i with relations (S_i)^2 = (S_i S_j)^15 = I. %C A167693 The initial terms coincide with those of A170741, although the two sequences are eventually different. %C A167693 Computed with MAGMA using commands similar to those used to compute A154638. %H A167693 G. C. Greubel, <a href="/A167693/b167693.txt">Table of n, a(n) for n = 0..500</a> %H A167693 <a href="/index/Rec#order_15">Index entries for linear recurrences with constant coefficients</a>, signature (20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, -210). %F A167693 G.f.: (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)/(210*t^15 - 20*t^14 - 20*t^13 - 20*t^12 - 20*t^11 - 20*t^10 - 20*t^9 - 20*t^8 - 20*t^7 - 20*t^6 - 20*t^5 - 20*t^4 - 20*t^3 - 20*t^2 - 20*t + 1). %t A167693 CoefficientList[Series[(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)/(210*t^15 - 20*t^14 - 20*t^13 - 20*t^12 - 20*t^11 - 20*t^10 - 20*t^9 - 20*t^8 - 20*t^7 - 20*t^6 - 20*t^5 - 20*t^4 - 20*t^3 - 20*t^2 - 20*t + 1), {t, 0, 50}], t] (* _G. C. Greubel_, Jun 20 2016 *) %K A167693 nonn %O A167693 0,2 %A A167693 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009