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A059509 Main diagonal of the array A059503. 2
1, 5, 19, 66, 216, 679, 2075, 6211, 18299, 53244, 153366, 438095, 1242709, 3504161, 9830371, 27454614, 76375860, 211732471, 585157679, 1612689439, 4433421131, 12160156560, 33284285874, 90931830431 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..1000

Index entries for sequences related to boustrophedon transform

Index entries for linear recurrences with constant coefficients, signature (6,-11,6,-1).

FORMULA

From Colin Barker, Nov 30 2012: (Start)

a(n) = 6*a(n-1) - 11*a(n-2) + 6*a(n-3) - a(n-4).

G.f.: x*(x^3-x+1)/(x^2-3*x+1)^2. (End)

a(n) = ((3 - n)*Fibonacci(2*n) - (5 - 8*n)*Fibonacci(2*n - 1))/5. - G. C. Greubel, Sep 10 2017

MATHEMATICA

Rest[CoefficientList[Series[x*(x^3 - x + 1)/(x^2 - 3*x + 1)^2, {x, 0, 50}], x]] (* or *) Table[((3 - n)*Fibonacci[2*n] - (5 - 8*n)*Fibonacci[2*n - 1])/5, {n, 1, 50}] (* G. C. Greubel, Sep 10 2017 *)

PROG

(PARI) Vec(x*(x^3-x+1)/(x^2-3*x+1)^2 + O(x^40)) \\ Michel Marcus, Sep 09 2017

CROSSREFS

Cf. A059503.

Sequence in context: A099448 A239618 A124806 * A137745 A005021 A067325

Adjacent sequences:  A059506 A059507 A059508 * A059510 A059511 A059512

KEYWORD

easy,nonn

AUTHOR

Floor van Lamoen, Jan 19 2001

STATUS

approved

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Last modified May 25 17:53 EDT 2020. Contains 334595 sequences. (Running on oeis4.)