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A041991 Denominators of continued fraction convergents to sqrt(518). 2
1, 1, 4, 25, 79, 104, 4655, 4759, 18932, 118351, 373985, 492336, 22036769, 22529105, 89624084, 560273609, 1770444911, 2330718520, 104322059791, 106652778311, 424280394724, 2652335146655, 8381285834689, 11033620981344, 493860609013825, 504894229995169 (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, 0, 0, 4734, 0, 0, 0, 0, 0, -1).

FORMULA

G.f.: -(x^10-x^9+4*x^8-25*x^7+79*x^6-104*x^5-79*x^4-25*x^3-4*x^2-x-1) / (x^12-4734*x^6+1). - Colin Barker, Nov 28 2013

a(n) = 4734*a(n-6) - a(n-12) for n>11. - Vincenzo Librandi, Jan 11 2014

MATHEMATICA

Denominator[Convergents[Sqrt[518], 30]] (* Harvey P. Dale, Jan 21 2013 *)

CoefficientList[Series[-(x^10 - x^9 + 4 x^8 - 25 x^7 + 79 x^6 - 104 x^5 - 79 x^4 - 25 x^3 - 4 x^2 - x - 1)/(x^12 - 4734 x^6 + 1), {x, 0, 40}], x] (* Vincenzo Librandi, Jan 11 2014 *)

PROG

(MAGMA) I:=[1, 1, 4, 25, 79, 104, 4655, 4759, 18932, 118351, 373985, 492336]; [n le 12 select I[n] else 4734*Self(n-6)-Self(n-12): n in [1..30]]; // Vincenzo Librandi, Jan 11 2014

CROSSREFS

Cf. A041990, A040495.

Sequence in context: A273361 A266126 A303514 * A027764 A095669 A323967

Adjacent sequences:  A041988 A041989 A041990 * A041992 A041993 A041994

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Nov 28 2013

STATUS

approved

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Last modified April 20 02:06 EDT 2019. Contains 322291 sequences. (Running on oeis4.)