A041439 Denominators of continued fraction convergents to sqrt(235).

1, 3, 91, 276, 8371, 25389, 770041, 2335512, 70835401, 214841715, 6516086851, 19763102268, 599409154891, 1817990566941, 55139126163121, 167235369056304, 5072200197852241, 15383835962613027, 466587279076243051, 1415145673191342180, 42920957474816508451

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, 92, 0, -1).

Formula

G.f.: -(x^2-3*x-1) / (x^4-92*x^2+1). - Colin Barker, Nov 17 2013

a(n) = 92*a(n-2) - a(n-4). - Vincenzo Librandi, Dec 17 2013

Mathematica

Denominator[Convergents[Sqrt[235], 30]] (* Vincenzo Librandi, Dec 17 2013 *)
LinearRecurrence[{0, 92, 0, -1}, {1, 3, 91, 276}, 30] (* Harvey P. Dale, May 05 2018 *)

Prog

(Magma) I:=[1, 3, 91, 276]; [n le 4 select I[n] else 92*Self(n-2)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, Dec 17 2013

Crossrefs

Cf. A041438, A176524, A040219.

Sequence in context: A115704 A066751 A115886 * A366219 A300419 A156754

Adjacent sequences: A041436 A041437 A041438 * A041440 A041441 A041442

Keyword

nonn,frac,easy

Author

N. J. A. Sloane.

Extensions

More terms from Colin Barker, Nov 17 2013

Status

approved