A042799 Denominators of continued fraction convergents to sqrt(930).

1, 2, 121, 244, 14761, 29766, 1800721, 3631208, 219673201, 442977610, 26798329801, 54039637212, 3269176562521, 6592392762254, 398812742297761, 804217877357776, 48651885383764321, 98107988644886418, 5935131204076949401, 11968370396798785220

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, 122, 0, -1).

Formula

G.f.: -(x^2-2*x-1) / (x^4-122*x^2+1). - Colin Barker, Dec 23 2013

a(n) = 122*a(n-2) - a(n-4) for n>3. - Vincenzo Librandi, Jan 29 2014

Maple

convert(sqrt(930), confrac, 30, cvgts): denom(cvgts); # Wesley Ivan Hurt, Dec 23 2013

Mathematica

Denominator[Convergents[Sqrt[930], 30]] (* Wesley Ivan Hurt, Dec 23 2013 *)

Prog

(Magma) I:=[1, 2, 121, 244]; [n le 4 select I[n] else 122*Self(n-2)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, Jan 29 2014

Crossrefs

Cf. A042798, A040899.

Sequence in context: A290247 A100012 A337989 * A281983 A217023 A332112

Adjacent sequences: A042796 A042797 A042798 * A042800 A042801 A042802

Keyword

nonn,frac,easy

Author

N. J. A. Sloane.

Extensions

Additional term from Colin Barker, Dec 23 2013

Status

approved