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A041647 Denominators of continued fraction convergents to sqrt(342). 2
1, 2, 73, 148, 5401, 10950, 399601, 810152, 29565073, 59940298, 2187415801, 4434771900, 161839204201, 328113180302, 11973913695073, 24275940570448, 885907774231201, 1796091489032850, 65545201379413801, 132886494247860452, 4849458994302390073 (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 (0,74,0,-1).

FORMULA

G.f.: -(x^2-2*x-1) / (x^4-74*x^2+1). - Colin Barker, Nov 20 2013

a(n) = 74*a(n-2) - a(n-4) for n>3. - Vincenzo Librandi, Dec 22 2013

MATHEMATICA

Denominator[Convergents[Sqrt[342], 30]] (* Harvey P. Dale, Oct 13 2012 *)

CoefficientList[Series[(1 + 2 x - x^2)/(x^4 - 74 x^2 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 22 2013 *)

PROG

(MAGMA) I:=[1, 2, 73, 148]; [n le 4 select I[n] else 74*Self(n-2)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Dec 22 2013

CROSSREFS

Cf. A041646, A040323.

Sequence in context: A324566 A276518 A297410 * A083018 A240174 A295172

Adjacent sequences:  A041644 A041645 A041646 * A041648 A041649 A041650

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Nov 20 2013

STATUS

approved

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Last modified October 19 22:55 EDT 2019. Contains 328244 sequences. (Running on oeis4.)