A042309 Denominators of continued fraction convergents to sqrt(681).

1, 10, 21, 52, 73, 125, 323, 2063, 14764, 46355, 107474, 153829, 2568738, 2722567, 8013872, 26764183, 195363153, 1198943101, 2593249355, 3792192456, 6385441811, 16563076078, 39511593967, 411679015748, 21446820412863, 214879883144378

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, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 21486332006830, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1).

Formula

a(n) = 21486332006830*a(n-24) - a(n-48) for n>47. - Vincenzo Librandi, Jan 20 2014

Mathematica

Denominator[Convergents[Sqrt[681], 30]] (* Vincenzo Librandi, Jan 20 2014 *)

Crossrefs

Cf. A042308.

Sequence in context: A122963 A067520 A219884 * A215757 A048697 A090076

Adjacent sequences: A042306 A042307 A042308 * A042310 A042311 A042312

Keyword

nonn,frac,easy

Author

N. J. A. Sloane.

Extensions

More terms from Vincenzo Librandi, Jan 20 2014

Status

approved