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A042747 Denominators of continued fraction convergents to sqrt(904). 2
1, 15, 901, 13530, 812701, 12204045, 733055401, 11008035060, 661215159001, 9929235420075, 596415340363501, 8956159340872590, 537965975792718901, 8078445796231656105, 485244713749692085201, 7286749152041612934120, 437690193836246468132401 (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, 902, 0, -1).

FORMULA

a(0)=1, a(1)=15, a(2)=901, a(3)=13530, a(n)=902*a(n-2)-a(n-4). - Harvey P. Dale, Sep 25 2013

G.f.: -(x^2-15*x-1) / ((x^2-30*x-1)*(x^2+30*x-1)). - Colin Barker, Nov 19 2013

MATHEMATICA

Denominator[Convergents[Sqrt[904], 30]] (* or *) LinearRecurrence[ {0, 902, 0, -1}, {1, 15, 901, 13530}, 30] (* Harvey P. Dale, Sep 25 2013 *)

PROG

(MAGMA) I:=[1, 15, 901, 13530]; [n le 4 select I[n] else 902*Self(n-2)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, Jan 28 2014

CROSSREFS

Cf. A042746, A040873.

Sequence in context: A249963 A157462 A268166 * A324423 A261067 A136419

Adjacent sequences:  A042744 A042745 A042746 * A042748 A042749 A042750

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

Additional term from Colin Barker, Nov 19 2013

STATUS

approved

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Last modified December 6 13:45 EST 2021. Contains 349563 sequences. (Running on oeis4.)