A041778 Numerators of continued fraction convergents to sqrt(410).

20, 81, 3260, 13121, 528100, 2125521, 85548940, 344321281, 13858400180, 55777922001, 2244975280220, 9035679042881, 363672136995460, 1463724227024721, 58912641217984300, 237114289098961921

Offset

0,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..130

Index entries for linear recurrences with constant coefficients, signature (0, 162, 0, -1).

Formula

From Colin Barker, Jul 16 2012: (Start)

a(n) = 162*a(n-2) - a(n-4).

G.f.: -(x^3-20*x^2-81*x-20)/(x^4-162*x^2+1). (End)

Mathematica

Numerator[Convergents[Sqrt[410], 40]] (* Vincenzo Librandi, Nov 13 2011 *)
LinearRecurrence[{0, 162, 0, -1}, {20, 81, 3260, 13121}, 30] (* Harvey P. Dale, Jul 19 2015 *)

Crossrefs

Cf. A041779.

Sequence in context: A244449 A041776 A103532 * A219473 A256869 A156389

Adjacent sequences: A041775 A041776 A041777 * A041779 A041780 A041781

Keyword

nonn,cofr,frac,easy,less

Author

N. J. A. Sloane

Status

approved