A042505 Denominators of continued fraction convergents to sqrt(780).

1, 1, 13, 14, 769, 783, 10165, 10948, 601357, 612305, 7949017, 8561322, 470260405, 478821727, 6216121129, 6694942856, 367743035353, 374437978209, 4860998773861, 5235436752070, 287574583385641, 292810020137711, 3801294825038173, 4094104845175884

Offset

0,3

Links

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

Index entries for linear recurrences with constant coefficients, signature (0,0,0,782,0,0,0,-1).

Formula

G.f.: -(x^2-x-1)*(x^4+14*x^2+1) / ((x^4-28*x^2+1)*(x^4+28*x^2+1)). - Colin Barker, Dec 16 2013

Mathematica

Denominator[Convergents[Sqrt[780], 30]] (* Vincenzo Librandi, Jan 23 2014 *)
LinearRecurrence[{0, 0, 0, 782, 0, 0, 0, -1}, {1, 1, 13, 14, 769, 783, 10165, 10948}, 30] (* Harvey P. Dale, Apr 18 2023 *)

Crossrefs

Cf. A042504, A040752.

Sequence in context: A041361 A041362 A041835 * A156371 A229957 A070640

Adjacent sequences: A042502 A042503 A042504 * A042506 A042507 A042508

Keyword

nonn,frac,easy

Author

N. J. A. Sloane.

Extensions

More terms from Colin Barker, Dec 16 2013

Status

approved