A041837 Denominators of continued fraction convergents to sqrt(439).

1, 1, 20, 21, 860, 881, 17599, 18480, 756799, 775279, 15487100, 16262379, 665982260, 682244639, 13628630401, 14310875040, 586063632001, 600374507041, 11993179265780, 12593553772821, 515735330178620, 528328883951441, 10553984125255999, 11082313009207440

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, 880, 0, 0, 0, -1).

Formula

G.f.: -(x^2-x-1)*(x^4+21*x^2+1) / (x^8-880*x^4+1). - Colin Barker, Nov 25 2013

a(n) = 880*a(n-4) - a(n-8) for n>7. - Vincenzo Librandi, Dec 25 2013

Mathematica

Denominator[Convergents[Sqrt[439], 30]] (* Vincenzo Librandi, Dec 25 2013 *)

Prog

(Magma) I:=[1, 1, 20, 21, 860, 881, 17599, 18480]; [n le 8 select I[n] else 880*Self(n-4)-Self(n-8): n in [1..40]]; // Vincenzo Librandi, Dec 25 2013

Crossrefs

Cf. A041836, A040418.

Sequence in context: A063012 A302205 A041836 * A041838 A128356 A109212

Adjacent sequences: A041834 A041835 A041836 * A041838 A041839 A041840

Keyword

nonn,frac,easy,less

Author

N. J. A. Sloane.

Extensions

More terms from Colin Barker, Nov 25 2013

Status

approved