A041275 Denominators of continued fraction convergents to sqrt(150).

1, 4, 97, 392, 9505, 38412, 931393, 3763984, 91267009, 368832020, 8943235489, 36141773976, 876345810913, 3541525017628, 85872946233985, 347033309953568, 8414672385119617, 34005722850432036, 824552020795488481

Offset

0,2

Links

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

Index entries for linear recurrences with constant coefficients, signature (0,98,0,-1).

Formula

G.f.: (1 +4*x -x^2)/(x^4 -98*x^2 +1). - Vincenzo Librandi, Dec 14 2013

a(n) = 98*a(n-2) - a(n-4). - Vincenzo Librandi, Dec 14 2013

Mathematica

Denominator[Convergents[Sqrt[150], 30]] (* or *) CoefficientList[Series[(1 + 4 x - x^2)/(x^4 - 98 x^2 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 14 2013 *)

Prog

(Magma) I:=[1, 4, 97, 392]; [n le 4 select I[n] else 98*Self(n-2)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Dec 14 2013

Crossrefs

Cf. A041274.

Sequence in context: A309483 A333539 A356808 * A024384 A368004 A320358

Adjacent sequences: A041272 A041273 A041274 * A041276 A041277 A041278

Keyword

nonn,frac,easy

Author

N. J. A. Sloane.

Status

approved