A042351 Denominators of continued fraction convergents to sqrt(702).

1, 2, 105, 212, 11129, 22470, 1179569, 2381608, 125023185, 252427978, 13251278041, 26754984060, 1404510449161, 2835775882382, 148864856333025, 300565488548432, 15778270260851489, 31857106010251410, 1672347782793924809, 3376552671598101028

Offset

0,2

Links

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

Index entries for linear recurrences with constant coefficients, signature (0,106,0,-1).

Formula

G.f.: -(x^2-2*x-1) / (x^4-106*x^2+1). - Colin Barker, Dec 09 2013

a(n) = 106*a(n-2) - a(n-4) for n>3. - Vincenzo Librandi, Jan 20 2014

Mathematica

Denominator[Convergents[Sqrt[702], 30]] (* Vincenzo Librandi, Jan 20 2014 *)
LinearRecurrence[{0, 106, 0, -1}, {1, 2, 105, 212}, 20] (* Harvey P. Dale, Apr 19 2020 *)

Prog

(Magma) I:=[1, 2, 105, 212]; [n le 4 select I[n] else 106*Self(n-2)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, Jan 20 2014

Crossrefs

Cf. A042350, A040675.

Sequence in context: A098653 A119433 A307227 * A258828 A156880 A280095

Adjacent sequences: A042348 A042349 A042350 * A042352 A042353 A042354

Keyword

nonn,frac,easy

Author

N. J. A. Sloane.

Extensions

Additional term from Colin Barker, Dec 09 2013

Status

approved