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A041619 Denominators of continued fraction convergents to sqrt(328). 2
1, 9, 325, 2934, 105949, 956475, 34539049, 311807916, 11259624025, 101648424141, 3670602893101, 33137074462050, 1196605283526901, 10802584626204159, 390089651826876625, 3521609451068093784 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Andrew Howroyd, Table of n, a(n) for n = 0..200 (terms 0..56 from Vincenzo Librandi)

Index entries for linear recurrences with constant coefficients, signature (0,326,0,-1).

FORMULA

From Colin Barker, Jul 16 2012: (Start)

a(n) = 326*a(n-2)-a(n-4).

G.f.: -(x^2-9*x-1)/((x^2-18*x-1)*(x^2+18*x-1)).

(End)

MATHEMATICA

Denominator[Convergents[Sqrt[328], 30]] (* Harvey P. Dale, Mar 01 2012 *)

CoefficientList[Series[- (x^2 - 9 x - 1)/((x^2 - 18 x - 1)(x^2 + 18 x - 1)), {x, 0, 30}], x] (* Vincenzo Librandi, Oct 25 2013 *)

CROSSREFS

Cf. A041618.

Sequence in context: A211091 A124070 A203763 * A111968 A289196 A266907

Adjacent sequences: A041616 A041617 A041618 * A041620 A041621 A041622

KEYWORD

nonn,cofr,frac,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified November 28 09:43 EST 2022. Contains 358407 sequences. (Running on oeis4.)