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A041995 Denominators of continued fraction convergents to sqrt(520). 2
1, 1, 5, 56, 229, 285, 12769, 13054, 64985, 727889, 2976541, 3704430, 165971461, 169675891, 844675025, 9461101166, 38689079689, 48150180855, 2157297037309, 2205447218164, 10979085909965, 122975392227779, 502880654821081, 625856047048860 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Index to sequences with linear recurrences with constant coefficients, signature (0,0,0,0,0,12998,0,0,0,0,0,-1).

FORMULA

G.f.: -(x^10 -x^9 +5*x^8 -56*x^7 +229*x^6 -285*x^5 -229*x^4 -56*x^3 -5*x^2 -x -1) / ((x^6 -114*x^3 -1)*(x^6 +114*x^3 -1)). - Colin Barker, Nov 28 2013

a(n) = 12998*a(n-6) - a(n-12) for n>11. - Vincenzo Librandi, Jan 12 2014

MATHEMATICA

Denominator[Convergents[Sqrt[520], 40]] (* Vincenzo Librandi, Jan 12 2014 *)

PROG

(MAGMA) I:=[1, 1, 5, 56, 229, 285, 12769, 13054, 64985, 727889, 2976541, 3704430]; [n le 12 select I[n] else 12998*Self(n-6)-Self(n-12): n in [1..30]]; // Vincenzo Librandi, Jan 12 2014

CROSSREFS

Cf. A041994, A040497.

Sequence in context: A067515 A072318 A174514 * A062125 A030060 A247710

Adjacent sequences:  A041992 A041993 A041994 * A041996 A041997 A041998

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Nov 28 2013

STATUS

approved

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Last modified December 22 17:45 EST 2014. Contains 252365 sequences.