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A041837 Denominators of continued fraction convergents to sqrt(439). 2
1, 1, 20, 21, 860, 881, 17599, 18480, 756799, 775279, 15487100, 16262379, 665982260, 682244639, 13628630401, 14310875040, 586063632001, 600374507041, 11993179265780, 12593553772821, 515735330178620, 528328883951441, 10553984125255999, 11082313009207440 (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, 880, 0, 0, 0, -1).

FORMULA

G.f.: -(x^2-x-1)*(x^4+21*x^2+1) / (x^8-880*x^4+1). - Colin Barker, Nov 25 2013

a(n) = 880*a(n-4) - a(n-8) for n>7. - Vincenzo Librandi, Dec 25 2013

MATHEMATICA

Denominator[Convergents[Sqrt[439], 30]] (* Vincenzo Librandi, Dec 25 2013 *)

PROG

(MAGMA) I:=[1, 1, 20, 21, 860, 881, 17599, 18480]; [n le 8 select I[n] else 880*Self(n-4)-Self(n-8): n in [1..40]]; // Vincenzo Librandi, Dec 25 2013

CROSSREFS

Cf. A041836, A040418.

Sequence in context: A063012 A302205 A041836 * A041838 A128356 A109212

Adjacent sequences:  A041834 A041835 A041836 * A041838 A041839 A041840

KEYWORD

nonn,frac,easy,less

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Nov 25 2013

STATUS

approved

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Last modified October 20 10:56 EDT 2018. Contains 316379 sequences. (Running on oeis4.)