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A041881 Denominators of continued fraction convergents to sqrt(462). 2
1, 2, 85, 172, 7309, 14790, 628489, 1271768, 54042745, 109357258, 4647047581, 9403452420, 399592049221, 808587550862, 34360269185425, 69529125921712, 2954583557897329, 5978696241716370, 254059825709984869, 514098347661686108, 21846190427500801405 (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 (0,86,0,-1).

FORMULA

G.f.: -(x^2 -2*x -1) / (x^4 -86*x^2 +1). - Colin Barker, Nov 26 2013

a(n) = 86*a(n-2) - a(n-4) for n>3. - Vincenzo Librandi, Dec 26 2013

MATHEMATICA

Denominator[Convergents[Sqrt[462], 30]] (* Harvey P. Dale, Sep 30 2011 *)

CoefficientList[Series[(1 + 2 x - x^2)/(x^4 - 86 x^2 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 26 2013 *)

PROG

(MAGMA) I:=[1, 2, 85, 172]; [n le 4 select I[n] else 86*Self(n-2)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Dec 26 2013

CROSSREFS

Cf. A041880, A040440.

Sequence in context: A244947 A078166 A101578 * A076542 A226842 A303892

Adjacent sequences:  A041878 A041879 A041880 * A041882 A041883 A041884

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Nov 26 2013

STATUS

approved

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Last modified December 12 07:58 EST 2018. Contains 318053 sequences. (Running on oeis4.)