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A041417 Denominators of continued fraction convergents to sqrt(223). 2
1, 1, 14, 15, 434, 449, 6271, 6720, 194431, 201151, 2809394, 3010545, 87104654, 90115199, 1258602241, 1348717440, 39022690561, 40371408001, 563850994574, 604222402575, 17482078266674, 18086300669249, 252603986966911, 270690287636160, 7831932040779391 (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, 448, 0, 0, 0, -1).

FORMULA

G.f.: -(x^2-x-1)*(x^4+15*x^2+1) / (x^8-448*x^4+1). - Colin Barker, Nov 17 2013

a(n) = 448*a(n-4) - a(n-8). - Vincenzo Librandi, Dec 17 2013

MATHEMATICA

Denominator[Convergents[Sqrt[223], 30]] (* Vincenzo Librandi, Dec 17 2013 *)

PROG

(MAGMA) I:=[1, 1, 14, 15, 434, 449, 6271, 6720]; [n le 8 select I[n] else 448*Self(n-4)-Self(n-8): n in [1..40]]; // Vincenzo Librandi, Dec 17 2013

CROSSREFS

Cf. A041416, A040208.

Sequence in context: A033050 A225757 A041416 * A041418 A042733 A225758

Adjacent sequences:  A041414 A041415 A041416 * A041418 A041419 A041420

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Nov 17 2013

STATUS

approved

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Last modified February 16 05:10 EST 2019. Contains 320140 sequences. (Running on oeis4.)