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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A041615 Denominators of continued fraction convergents to sqrt(326). 2
1, 18, 649, 11700, 421849, 7604982, 274201201, 4943226600, 178230358801, 3213089685018, 115849459019449, 2088503352035100, 75301970132283049, 1357523965733129982, 48946164736524962401, 882388489223182453200, 31814931776771093277601 (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 (0,650,0,-1).

FORMULA

G.f.: -(x^2-18*x-1) / (x^4-650*x^2+1). - Colin Barker, Nov 20 2013

a(n) = 650*a(n-2) - a(n-4) for n>3. - Vincenzo Librandi, Dec 22 2013

MATHEMATICA

Denominator[Convergents[Sqrt[326], 20]] (* Harvey P. Dale, Jul 06 2013 *)

CoefficientList[Series[(1 + 18 x - x^2)/(x^4 - 650 x^2 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 22 2013 *)

PROG

(MAGMA) I:=[1, 18, 649, 11700]; [n le 4 select I[n] else 650*Self(n-2)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Dec 22 2013

CROSSREFS

Cf. A041614, A040307.

Sequence in context: A322889 A003298 A049869 * A041612 A046674 A073421

Adjacent sequences:  A041612 A041613 A041614 * A041616 A041617 A041618

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Nov 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 November 14 22:17 EST 2019. Contains 329134 sequences. (Running on oeis4.)