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A042397 Denominators of continued fraction convergents to sqrt(725). 2
1, 1, 13, 27, 337, 364, 19265, 19629, 254813, 529255, 6605873, 7135128, 377632529, 384767657, 4994844413, 10374456483, 129488322209, 139862778692, 7402352814193, 7542215592885, 97908939928813, 203360095450511, 2538230085334945, 2741590180785456 (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, 19602, 0, 0, 0, 0, 0, -1).

FORMULA

G.f.: -(x^10 -x^9 +13*x^8 -27*x^7 +337*x^6 -364*x^5 -337*x^4 -27*x^3 -13*x^2 -x -1) / ((x^2 -5*x -1)*(x^2 +5*x -1)*(x^4 -5*x^3 +26*x^2 +5*x +1)*(x^4 +5*x^3 +26*x^2 -5*x +1)). - Colin Barker, Dec 10 2013

MATHEMATICA

Denominator[Convergents[Sqrt[725], 30]] (* Harvey P. Dale, May 07 2013 *)

CoefficientList[Series[-(x^10 - x^9 + 13 x^8 - 27 x^7 + 337 x^6 - 364 x^5 - 337 x^4 - 27 x^3 - 13 x^2 - x - 1)/((x^2 - 5 x - 1) (x^2 + 5 x - 1) (x^4 - 5 x^3 + 26 x^2 + 5 x + 1) (x^4 + 5 x^3 + 26 x^2 - 5 x + 1)), {x, 0, 30}], x] (* Vincenzo Librandi, Jan 21 2014 *)

CROSSREFS

Cf. A042396, A040698.

Sequence in context: A146380 A146372 A018946 * A041336 A145417 A157206

Adjacent sequences:  A042394 A042395 A042396 * A042398 A042399 A042400

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Dec 10 2013

STATUS

approved

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Last modified October 28 03:58 EDT 2021. Contains 348313 sequences. (Running on oeis4.)