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A042089 Denominators of continued fraction convergents to sqrt(568). 2
1, 1, 5, 6, 281, 287, 1429, 1716, 80365, 82081, 408689, 490770, 22984109, 23474879, 116883625, 140358504, 6573374809, 6713733313, 33428308061, 40142041374, 1879962211265, 1920104252639, 9560379221821, 11480483474460, 537662619046981, 549143102521441 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Index entries for linear recurrences with constant coefficients, signature (0,0,0,286,0,0,0,-1).

FORMULA

G.f.: (1 + x - x^2)*(1 + 6*x^2 + x^4)/(1 - 286*x^4 + x^8). - Colin Barker, Dec 01 2013

a(n) = 286*a(n-4) - a(n-8) for n>7. - Vincenzo Librandi, Jan 14 2014

MATHEMATICA

Denominator[Convergents[Sqrt[568], 30]] (* Vincenzo Librandi, Jan 14 2014 *)

PROG

(MAGMA) I:=[1, 1, 5, 6, 281, 287, 1429, 1716]; [n le 8 select I[n] else 286*Self(n-4)-Self(n-8): n in [1..40]]; // Vincenzo Librandi, Jan 14 2014

CROSSREFS

Cf. A042088, A040544.

Sequence in context: A041601 A301648 A041827 * A156191 A042387 A007666

Adjacent sequences:  A042086 A042087 A042088 * A042090 A042091 A042092

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Dec 01 2013

STATUS

approved

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Last modified February 17 17:47 EST 2019. Contains 320222 sequences. (Running on oeis4.)