A042909 Denominators of continued fraction convergents to sqrt(986).

1, 2, 5, 312, 629, 1570, 97969, 197508, 492985, 30762578, 62018141, 154798860, 9659547461, 19473893782, 48607335025, 3033128665332, 6114864665689, 15262857996710, 952412060461709, 1920086978920128, 4792586018301965, 299060420113641958, 602913426245585881

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, 314, 0, 0, 1).

Formula

G.f.: -(x^4-2*x^3+5*x^2+2*x+1) / (x^6+314*x^3-1). - Colin Barker, Dec 25 2013

a(n) = 314*a(n-3) + a(n-6) for n>5. - Vincenzo Librandi, Feb 01 2014

Mathematica

Denominator[Convergents[Sqrt[986], 30]] (* Vincenzo Librandi, Feb 01 2014 *)

Prog

(Magma) I:=[1, 2, 5, 312, 629, 1570]; [n le 6 select I[n] else 314*Self(n-3)+Self(n-6): n in [1..30]]; // Vincenzo Librandi, Feb 01 2014

Crossrefs

Cf. A042908, A040954.

Sequence in context: A248961 A353050 A308270 * A270476 A345977 A183129

Adjacent sequences: A042906 A042907 A042908 * A042910 A042911 A042912

Keyword

nonn,frac,easy

Author

N. J. A. Sloane.

Extensions

More terms from Colin Barker, Dec 25 2013

Status

approved