A041271 Denominators of continued fraction convergents to sqrt(148).

1, 6, 145, 876, 21169, 127890, 3090529, 18671064, 451196065, 2725847454, 65871534961, 397955057220, 9616792908241, 58098712506666, 1403985893068225, 8482014070916016, 204972323595052609, 1238315955641231670, 29924555258984612689, 180785647509548907804

Offset

0,2

Links

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

Index entries for linear recurrences with constant coefficients, signature (0,146,0,-1).

Formula

From Vincenzo Librandi, Dec 14 2013: (Start)

a(n) = (1 + 6*x - x^2)/(x^4 - 146*x^2 + 1).

a(n) = 146*a(n-2) - a(n-4). (End)

Mathematica

Denominator[Convergents[Sqrt[148], 30]] (* or *) CoefficientList[Series[(1 + 6 x - x^2)/(x^4 - 146 x^2 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 14 2013 *)

Prog

(Magma) I:=[1, 6, 145, 876]; [n le 4 select I[n] else 146*Self(n-2)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Dec 14 2013

Crossrefs

Cf. A041270.

Sequence in context: A133460 A166953 A280847 * A196964 A121473 A166837

Adjacent sequences: A041268 A041269 A041270 * A041272 A041273 A041274

Keyword

nonn,frac,easy

Author

N. J. A. Sloane

Extensions

More terms from Vincenzo Librandi, Dec 14 2013

Status

approved