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A179133 Denominators of A178381(4*n+3)/A178381(4*n+2) 7
2, 4, 5, 26, 68, 89, 466, 1220, 1597, 8362, 21892, 28657, 150050, 392836, 514229, 2692538, 7049156, 9227465, 48315634, 126491972, 165580141, 866988874, 2269806340, 2971215073, 15557484098, 40730022148, 53316291173, 279167724890 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

For the numerators see A128052.

LINKS

Table of n, a(n) for n=0..27.

FORMULA

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

EXAMPLE

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

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

MAPLE

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);

CROSSREFS

Cf. A179131 and A179132.

Sequence in context: A036984 A163891 A036985 * A277371 A199929 A126666

Adjacent sequences:  A179130 A179131 A179132 * A179134 A179135 A179136

KEYWORD

easy,frac,nonn

AUTHOR

Johannes W. Meijer, Jul 01 2010

STATUS

approved

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Last modified July 22 02:26 EDT 2019. Contains 325210 sequences. (Running on oeis4.)