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 A179133 Denominators of A178381(4*n+3)/A178381(4*n+2) 7

%I

%S 2,4,5,26,68,89,466,1220,1597,8362,21892,28657,150050,392836,514229,

%T 2692538,7049156,9227465,48315634,126491972,165580141,866988874,

%U 2269806340,2971215073,15557484098,40730022148,53316291173,279167724890

%N Denominators of A178381(4*n+3)/A178381(4*n+2)

%C For the numerators see A128052.

%F Conjecture: a(n) = 18*a(n-3)-a(n-6). G.f.: -(x^5+4*x^4+10*x^3-5*x^2-4*x-2) / ((x^2-3*x+1)*(x^4+3*x^3+8*x^2+3*x+1)). - _Colin Barker_, Jun 27 2013

%e a(n) = (A179134(n)*A153727(n+1))/2

%e Limit(A128052(n+1)/A179133(n), n =infinity) = 1+cos(Pi/5)

%p with(GraphTheory): nmax:=120; P:=9: G:=PathGraph(P): A:= AdjacencyMatrix(G): for n from 0 to nmax do B(n):=A^n; A178381(n):=add(B(n)[1,k],k=1..P); od: for n from 0 to nmax-1 do a(n):= denom(A178381(4*n+3)/A178381(4*n+2)) od: seq(a(n),n=0..nmax/4-1);

%Y Cf. A179131 and A179132.

%K easy,frac,nonn

%O 0,1

%A _Johannes W. Meijer_, Jul 01 2010

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Last modified October 19 23:44 EDT 2019. Contains 328244 sequences. (Running on oeis4.)