A166433 Number of reduced words of length n in Coxeter group on 39 generators S_i with relations (S_i)^2 = (S_i S_j)^11 = I.
1, 39, 1482, 56316, 2140008, 81320304, 3090171552, 117426518976, 4462207721088, 169563893401344, 6443427949251072, 244850262071539995, 9304309958718491652, 353563778431301613513, 13435423580389420681500
Offset: 0
Keywords
Links
- G. C. Greubel, Table of n, a(n) for n = 0..500
- Index entries for linear recurrences with constant coefficients, signature (37,37,37,37,37,37,37,37,37,37,-703).
Programs
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Magma
R
:=PowerSeriesRing(Integers(), 30); Coefficients(R!( (1+x)*(1-x^11)/(1-38*x+740*x^11-703*x^12) )); // G. C. Greubel, Jul 25 2024 -
Mathematica
With[{p=703, q=37}, CoefficientList[Series[(1+t)*(1-t^11)/(1 - (q+1)*t + (p+q)*t^11 - p*t^12), {t,0,40}], t]] (* G. C. Greubel, May 14 2016; Jul 25 2024 *) coxG[{11,703,-37}] (* The coxG program is at A169452 *) (* Harvey P. Dale, Feb 06 2019 *)
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SageMath
def A166423_list(prec): P.
= PowerSeriesRing(ZZ, prec) return P( (1+x)*(1-x^11)/(1-38*x+740*x^11-703*x^12) ).list() A166423_list(30) # G. C. Greubel, Jul 25 2024
Formula
G.f.: (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)/(703*t^11 - 37*t^10 - 37*t^9 - 37*t^8 - 37*t^7 - 37*t^6 - 37*t^5 - 37*t^4 - 37*t^3 - 37*t^2 - 37*t + 1).
From G. C. Greubel, Jul 25 2024: (Start)
a(n) = 37*Sum_{j=1..10} a(n-j) - 703*a(n-11).
G.f.: (1+x)*(1-x^11)/(1 - 38*x + 740*x^11 - 703*x^12). (End)
Comments