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A041575 Denominators of continued fraction convergents to sqrt(305). 2
1, 2, 13, 28, 965, 1958, 12713, 27384, 943769, 1914922, 12433301, 26781524, 923005117, 1872791758, 12159755665, 26192303088, 902698060657, 1831588424402, 11892228607069, 25616045638540, 882837780317429, 1791291606273398, 11630587417957817, 25052466442189032 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

Index entries for linear recurrences with constant coefficients, signature (0,0,0,978,0,0,0,-1).

FORMULA

G.f.: -(x^2-2*x-1)*(x^4+14*x^2+1) / (x^8-978*x^4+1). - Colin Barker, Nov 19 2013

a(n) = 978*a(n-4) - a(n-8) for n>7. - Vincenzo Librandi, Dec 20 2013

MATHEMATICA

Denominator[Convergents[Sqrt[305], 30]] (* Vincenzo Librandi, Dec 20 2013 *)

LinearRecurrence[{0, 0, 0, 978, 0, 0, 0, -1}, {1, 2, 13, 28, 965, 1958, 12713, 27384}, 30] (* Harvey P. Dale, Nov 03 2015 *)

PROG

(MAGMA) I:=[1, 2, 13, 28, 965, 1958, 12713, 27384]; [n le 8 select I[n] else 978*Self(n-4)-Self(n-8): n in [1..40]]; // Vincenzo Librandi, Dec 20 2013

CROSSREFS

Cf. A041574, A040287.

Sequence in context: A294559 A041017 A033837 * A042917 A174049 A141336

Adjacent sequences:  A041572 A041573 A041574 * A041576 A041577 A041578

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Nov 19 2013

STATUS

approved

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Last modified February 21 04:18 EST 2019. Contains 320371 sequences. (Running on oeis4.)