A042798 Numerators of continued fraction convergents to sqrt(930).

30, 61, 3690, 7441, 450150, 907741, 54914610, 110736961, 6699132270, 13509001501, 817239222330, 1647987446161, 99696485991990, 201040959430141, 12162154051800450, 24525349063031041, 1483683097833662910, 2991891544730356861, 180997175781655074570

Offset

0,1

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.: (30 +61*x +30*x^2 -x^3)/(1 -122*x^2 +x^4), - Vincenzo Librandi, Dec 05 2013

a(n) = 122*a(n-2) - a(n-4). - Vincenzo Librandi, Dec 05 2013

Mathematica

Numerator[Convergents[Sqrt[930], 30]] (* Harvey P. Dale, Apr 27 2012 *)
CoefficientList[Series[(30 + 61 x + 30 x^2 - x^3)/(1 - 122 x^2 + x^4), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 05 2013 *)

Prog

(Magma) I:=[30, 61, 3690, 7441]; [n le 4 select I[n] else 122*Self(n-2)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, Dec 05 2013

Crossrefs

Cf. A042799.

Sequence in context: A042792 A042794 A042796 * A320705 A132771 A326158

Adjacent sequences: A042795 A042796 A042797 * A042799 A042800 A042801

Keyword

nonn,cofr,frac,easy

Author

N. J. A. Sloane.

Extensions

More terms from Vincenzo Librandi, Dec 05 2013

Status

approved