A042749 Denominators of continued fraction convergents to sqrt(905).

1, 12, 721, 8664, 520561, 6255396, 375844321, 4516387248, 271359079201, 3260825337660, 195920879338801, 2354311377403272, 141454603523535121, 1699809553659824724, 102130027823113018561, 1227260143431016047456, 73737738633684075865921

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, 722, 0, -1).

Formula

G.f.: -(x^2-12*x-1) / (x^4-722*x^2+1). - Colin Barker, Dec 22 2013

Mathematica

Denominator[Convergents[Sqrt[905], 30]] (* Vincenzo Librandi, Jan 28 2014 *)
LinearRecurrence[{0, 722, 0, -1}, {1, 12, 721, 8664}, 20] (* Harvey P. Dale, Nov 08 2017 *)

Crossrefs

Cf. A042748, A040874.

Sequence in context: A381359 A162447 A061025 * A219568 A202792 A341560

Adjacent sequences: A042746 A042747 A042748 * A042750 A042751 A042752

Keyword

nonn,frac,easy

Author

N. J. A. Sloane.

Extensions

Additional term from Colin Barker, Dec 22 2013

Status

approved