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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A042768 Numerators of continued fraction convergents to sqrt(915). 2
30, 121, 7290, 29281, 1764150, 7085881, 426917010, 1714753921, 103312152270, 414963363001, 25001113932330, 100419419092321, 6050166259471590, 24301084456978681, 1464115233678192450, 5880762019169748481, 354309836383863101310, 1423120107554622153721 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Index entries for linear recurrences with constant coefficients, signature (0, 242, 0, -1).

FORMULA

G.f.: (30 +121*x +30*x^2 -x^3)/(1 -242*x^2 +x^4). - Vincenzo Librandi, Dec 04 2013

a(n) = 242*a(n-2) - a(n-4). - Vincenzo Librandi, Dec 04 2013

MATHEMATICA

Numerator[Convergents[Sqrt[915], 30]] (* or *) CoefficientList[Series[(30 + 121 x + 30 x^2 - x^3)/(1 - 242 x^2 + x^4), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 04 2013 *)

PROG

(MAGMA) I:=[30, 121, 7290, 29281]; [n le 4 select I[n] else 242*Self(n-2)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, Dec 04 2013

CROSSREFS

Cf. A042769.

Sequence in context: A042764 A219223 A042766 * A122137 A003901 A010744

Adjacent sequences:  A042765 A042766 A042767 * A042769 A042770 A042771

KEYWORD

nonn,cofr,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Vincenzo Librandi, Dec 04 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 March 18 16:00 EDT 2019. Contains 321292 sequences. (Running on oeis4.)