login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A042673 Denominators of continued fraction convergents to sqrt(866). 2
1, 2, 5, 7, 201, 208, 617, 1442, 84253, 169948, 424149, 594097, 17058865, 17652962, 52364789, 122382540, 7150552109, 14423486758, 35997525625, 50421012383, 1447785872349, 1498206884732, 4444199641813, 10386606168358, 606867357406577, 1224121320981512 (list; graph; refs; listen; history; text; internal format)
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, 84870, 0, 0, 0, 0, 0, 0, 0, -1).

FORMULA

G.f.: -(x^14 -2*x^13 +5*x^12 -7*x^11 +201*x^10 -208*x^9 +617*x^8 -1442*x^7 -617*x^6 -208*x^5 -201*x^4 -7*x^3 -5*x^2 -2*x -1) / (x^16 -84870*x^8 +1). - Colin Barker, Dec 20 2013

a(n) = 84870*a(n-8) - a(n-16) for n>15. - Vincenzo Librandi, Dec 20 2013

MATHEMATICA

Denominator[Convergents[Sqrt[866], 30]] (* Vincenzo Librandi, Dec 20 2013 *)

PROG

(MAGMA) I:=[1, 2, 5, 7, 201, 208, 617, 1442, 84253, 169948, 424149, 594097, 17058865, 17652962, 52364789, 122382540]; [n le 16 select I[n] else 84870*Self(n-8)-Self(n-16): n in [1..40]]; // Vincenzo Librandi, Dec 20 2013

CROSSREFS

Cf. A042672, A040836.

Sequence in context: A242169 A058854 A006275 * A214705 A252283 A007571

Adjacent sequences:  A042670 A042671 A042672 * A042674 A042675 A042676

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Dec 20 2013

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 27 04:13 EDT 2021. Contains 346303 sequences. (Running on oeis4.)