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A041517 Denominators of continued fraction convergents to sqrt(275). 2
1, 1, 2, 5, 7, 12, 391, 403, 794, 1991, 2785, 4776, 155617, 160393, 316010, 792413, 1108423, 1900836, 61935175, 63836011, 125771186, 315378383, 441149569, 756527952, 24650044033, 25406571985, 50056616018, 125519804021, 175576420039, 301096224060 (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, 0, 0, 398, 0, 0, 0, 0, 0, -1).

FORMULA

G.f.: -(x^4-x^3+2*x^2+x+1)*(x^6-6*x^3-1) / ((x^6-20*x^3+1)*(x^6+20*x^3+1)). - Colin Barker, Nov 18 2013

a(n) = 398*a(n-6) - a(n-12) for n>11. - Vincenzo Librandi, Dec 19 2013

MATHEMATICA

Denominator[Convergents[Sqrt[275], 30]] (* Vincenzo Librandi, Dec 19 2013 *)

PROG

(MAGMA) I:=[1, 1, 2, 5, 7, 12, 391, 403, 794, 1991, 2785, 4776]; [n le 12 select I[n] else 398*Self(n-6)-Self(n-12): n in [1..30]]; // Vincenzo Librandi, Dec 19 2013

CROSSREFS

Cf. A041516, A040258.

Sequence in context: A041033 A134472 A041203 * A041975 A042577 A092792

Adjacent sequences:  A041514 A041515 A041516 * A041518 A041519 A041520

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Colin Barker, Nov 18 2013

STATUS

approved

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Last modified February 16 21:22 EST 2019. Contains 320199 sequences. (Running on oeis4.)