cp's OEIS Frontend

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.

A163179 Number of reduced words of length n in Coxeter group on 27 generators S_i with relations (S_i)^2 = (S_i S_j)^4 = I.

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%I A163179 #8 Mar 23 2020 07:07:25
%S A163179 1,27,702,18252,474201,12320100,320085675,8316067500,216057716550,
%T A163179 5613342710625,145838884522500,3789004401804375,98441196968058750,
%U A163179 2557576669978687500,66447774146243953125,1726363373899181062500
%N A163179 Number of reduced words of length n in Coxeter group on 27 generators S_i with relations (S_i)^2 = (S_i S_j)^4 = I.
%C A163179 The initial terms coincide with those of A170746, although the two sequences are eventually different.
%C A163179 Computed with MAGMA using commands similar to those used to compute A154638.
%H A163179 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (25,25,25,-325).
%F A163179 G.f.: (t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(325*t^4 - 25*t^3 - 25*t^2 - 25*t + 1).
%o A163179 (PARI) Vec((t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(325*t^4 - 25*t^3 - 25*t^2 - 25*t + 1) + O(t^20)) \\ _Jinyuan Wang_, Mar 23 2020
%K A163179 nonn
%O A163179 0,2
%A A163179 _John Cannon_ and _N. J. A. Sloane_, Dec 03 2009