login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A042925 Denominators of continued fraction convergents to sqrt(994). 2
1, 1, 2, 17, 19, 36, 2251, 2287, 4538, 38591, 43129, 81720, 5109769, 5191489, 10301258, 87601553, 97902811, 185504364, 11599173379, 11784677743, 23383851122, 198855486719, 222239337841, 421094824560, 26330118460561, 26751213285121, 53081331745682 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

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, 2270, 0, 0, 0, 0, 0, -1).

FORMULA

G.f.: -(x^4-x^3+2*x^2+x+1)*(x^6-18*x^3-1) / (x^12-2270*x^6+1). - Colin Barker, Dec 25 2013

a(n) = 2270*a(n-6) - a(n-12) for n>11. - Vincenzo Librandi, Feb 01 2014

MATHEMATICA

Denominator[Convergents[Sqrt[994], 30]] (* Vincenzo Librandi, Feb 01 2014 *)

LinearRecurrence[{0, 0, 0, 0, 0, 2270, 0, 0, 0, 0, 0, -1}, {1, 1, 2, 17, 19, 36, 2251, 2287, 4538, 38591, 43129, 81720}, 30] (* Harvey P. Dale, Oct 27 2018 *)

PROG

(MAGMA) I:=[1, 1, 2, 17, 19, 36, 2251, 2287, 4538, 38591, 43129, 81720]; [n le 12 select I[n] else 2270*Self(n-6)-Self(n-12): n in [1..30]]; // Vincenzo Librandi, Feb 01 2014

CROSSREFS

Cf. A042924, A040962.

Sequence in context: A018569 A022118 A041339 * A019413 A040138 A240475

Adjacent sequences:  A042922 A042923 A042924 * A042926 A042927 A042928

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Dec 25 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 October 20 12:47 EDT 2019. Contains 328257 sequences. (Running on oeis4.)