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 A168837 #8 Nov 24 2016 18:33:24 %S A168837 1,16,240,3600,54000,810000,12150000,182250000,2733750000,41006250000, %T A168837 615093750000,9226406250000,138396093750000,2075941406250000, %U A168837 31139121093750000,467086816406250000,7006302246093750000 %N A168837 Number of reduced words of length n in Coxeter group on 16 generators S_i with relations (S_i)^2 = (S_i S_j)^20 = I. %C A168837 The initial terms coincide with those of A170735, although the two sequences are eventually different. %C A168837 First disagreement at index 20: a(20) = 354694051208496093749880, A170735(20) = 354694051208496093750000. - Klaus Brockhaus, Apr 02 2011 %C A168837 Computed with MAGMA using commands similar to those used to compute A154638. %H A168837 <a href="/index/Rec#order_20">Index entries for linear recurrences with constant coefficients</a>, signature (14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, -105). %F A168837 G.f.: (t^20 + 2*t^19 + 2*t^18 + 2*t^17 + 2*t^16 + 2*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)/(105*t^20 - 14*t^19 - 14*t^18 - 14*t^17 - 14*t^16 - 14*t^15 - 14*t^14 - 14*t^13 - 14*t^12 - 14*t^11 - 14*t^10 - 14*t^9 - 14*t^8 - 14*t^7 - 14*t^6 - 14*t^5 - 14*t^4 - 14*t^3 - 14*t^2 - 14*t + 1). %Y A168837 Cf. A170735 (G.f.: (1+x)/(1-15*x)). %K A168837 nonn %O A168837 0,2 %A A168837 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009