A042555 Denominators of continued fraction convergents to sqrt(806).

1, 2, 3, 5, 18, 41, 223, 933, 4888, 10709, 37015, 47724, 84739, 217202, 12248051, 24713304, 36961355, 61674659, 221985332, 505645323, 2750211947, 11506493111, 60282677502, 132071848115, 456498221847, 588570069962, 1045068291809, 2678706653580

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, 12332790, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1).

Formula

a(n) = 12332790*a(n-14) - a(n-28) for n > 27. - Vincenzo Librandi, Jan 25 2014

Mathematica

Denominator[Convergents[Sqrt[806], 30]] (* Vincenzo Librandi, Jan 25 2014 *)
LinearRecurrence[{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 12332790, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1}, {1, 2, 3, 5, 18, 41, 223, 933, 4888, 10709, 37015, 47724, 84739, 217202, 12248051, 24713304, 36961355, 61674659, 221985332, 505645323, 2750211947, 11506493111, 60282677502, 132071848115, 456498221847, 588570069962, 1045068291809, 2678706653580}, 30] (* Harvey P. Dale, May 26 2018 *)

Prog

(PARI) vector(30, i, contfracpnqn(contfrac(sqrt(806), i))[2, 1]) \\ Jinyuan Wang, Feb 28 2020

Crossrefs

Cf. A040777, A042554.

Sequence in context: A284530 A041293 A041713 * A041891 A042813 A128532

Adjacent sequences: A042552 A042553 A042554 * A042556 A042557 A042558

Keyword

nonn,frac,easy

Author

N. J. A. Sloane

Extensions

More terms from Vincenzo Librandi, Jan 25 2014

Status

approved