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A042857 Denominators of continued fraction convergents to sqrt(959). 2
1, 1, 30, 31, 1890, 1921, 57599, 59520, 3628799, 3688319, 110590050, 114278369, 6967292190, 7081570559, 212332838401, 219414408960, 13377197376001, 13596611784961, 407678939139870, 421275550924831, 25684211994629730, 26105487545554561, 782743350815711999 (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, 1920, 0, 0, 0, -1).

FORMULA

G.f.: -(x^2-x-1)*(x^4+31*x^2+1) / (x^8-1920*x^4+1). - Colin Barker, Dec 25 2013

a(n) = 1920*a(n-4) - a(n-8) for n>7. - Vincenzo Librandi, Dec 25 2013

MATHEMATICA

Denominator[Convergents[Sqrt[959], 30]] (* Vincenzo Librandi, Dec 25 2013 *)

PROG

(MAGMA) I:=[1, 1, 30, 31, 1890, 1921, 57599, 59520]; [n le 8 select I[n] else 1920*Self(n-4)-Self(n-8): n in [1..40]]; // Vincenzo Librandi, Dec 25 2013

CROSSREFS

Cf. A042856, A040928.

Sequence in context: A042854 A268337 A042856 * A042858 A175514 A043584

Adjacent sequences:  A042854 A042855 A042856 * A042858 A042859 A042860

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Dec 25 2013

STATUS

approved

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Last modified February 18 06:21 EST 2019. Contains 320245 sequences. (Running on oeis4.)