A041239 Denominators of continued fraction convergents to sqrt(131).

1, 2, 9, 101, 413, 927, 20807, 42541, 190971, 2143222, 8763859, 19670940, 441524539, 902720018, 4052404611, 45479170739, 185969087567, 417417345873, 9369150696773, 19155718739419, 85992025654449

Offset

0,2

Links

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

Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,21220,0,0,0,0,0,-1).

Formula

a(n) = 21220*a(n-6)-a(n-12). G.f.: -(x^10-2*x^9+9*x^8-101*x^7+413*x^6-927*x^5-413*x^4-101*x^3-9*x^2-2*x-1)/(x^12-21220*x^6+1). [Colin Barker, Jul 19 2012]

Mathematica

Denominator[Convergents[Sqrt[131], 30]] (* Vincenzo Librandi, Oct 24 2013 *)

Crossrefs

Cf. A041238.

Sequence in context: A013520 A378045 A369673 * A098610 A226391 A348858

Adjacent sequences: A041236 A041237 A041238 * A041240 A041241 A041242

Keyword

nonn,cofr,frac,easy

Author

N. J. A. Sloane.

Status

approved