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!)
A041495 Denominators of continued fraction convergents to sqrt(264). 3
1, 4, 129, 520, 16769, 67596, 2179841, 8786960, 283362561, 1142237204, 36834953089, 148482049560, 4788260539009, 19301524205596, 622437035118081, 2509049664677920, 80912026304811521, 326157154883924004, 10517940982590379649, 42397921085245442600 (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 (0,130,0,-1).

FORMULA

G.f.: (1+4*x-x^2)/(1-130*x^2+x^4). - Colin Barker, Nov 18 2013

a(n) = 130*a(n-2) - a(n-4) for n>3. - Vincenzo Librandi, Dec 18 2013

a(2n) = A041115(2n), a(2n+1) = A041115(2n+1)/2. - M. F. Hasler, Feb 24 2020

MATHEMATICA

Denominator[Convergents[Sqrt[264], 30]] (* Vincenzo Librandi, Dec 18 2013 *)

PROG

(MAGMA) I:=[1, 4, 129, 520]; [n le 4 select I[n] else 130*Self(n-2)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, Dec 18 2013

(PARI) apply( {A041495(n)=([130, -1; 1, 0]^(n\2))[1, ]*[4^n%=2, 1-n]~}, [0..20]) \\ M. F. Hasler, Feb 24 2020

CROSSREFS

Cf. A040247, A041115, A041494.

Sequence in context: A146555 A305568 A057134 * A188315 A298274 A299136

Adjacent sequences:  A041492 A041493 A041494 * A041496 A041497 A041498

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Colin Barker, Nov 18 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 August 13 19:30 EDT 2020. Contains 336451 sequences. (Running on oeis4.)