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A041813 Denominators of continued fraction convergents to sqrt(427). 2
1, 1, 2, 3, 122, 125, 247, 372, 15127, 15499, 30626, 46125, 1875626, 1921751, 3797377, 5719128, 232562497, 238281625, 470844122, 709125747, 28835874002, 29544999749, 58380873751, 87925873500, 3575415813751, 3663341687251, 7238757501002, 10902099188253 (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, 124, 0, 0, 0, -1).

FORMULA

G.f.: -(x^2-x-1)*(x^4+3*x^2+1) / (x^8-124*x^4+1). - Colin Barker, Nov 25 2013

a(n) = 124*a(n-4) - a(n-8) for n>7. - Vincenzo Librandi, Dec 24 2013

MATHEMATICA

Denominator[Convergents[Sqrt[427], 30]] (* Vincenzo Librandi, Dec 24 2013 *)

LinearRecurrence[{0, 0, 0, 124, 0, 0, 0, -1}, {1, 1, 2, 3, 122, 125, 247, 372}, 30] (* Harvey P. Dale, Jan 20 2019 *)

PROG

(MAGMA) I:=[1, 1, 2, 3, 122, 125, 247, 372]; [n le 8 select I[n] else 124*Self(n-4)-Self(n-8): n in [1..50]]; // Vincenzo Librandi, Dec 24 2013

CROSSREFS

Cf. A041812, A040406.

Sequence in context: A152838 A208247 A102697 * A065842 A065841 A051177

Adjacent sequences:  A041810 A041811 A041812 * A041814 A041815 A041816

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Nov 25 2013

STATUS

approved

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Last modified April 18 11:07 EDT 2019. Contains 322209 sequences. (Running on oeis4.)