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!)
A042297 Denominators of continued fraction convergents to sqrt(674). 2
1, 1, 25, 26, 1325, 1351, 33749, 35100, 1788749, 1823849, 45561125, 47384974, 2414809825, 2462194799, 61507485001, 63969679800, 3259991475001, 3323961154801, 83035059190225, 86359020345026, 4400986076441525, 4487345096786551, 112097268399318749 (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 (0,0,0,1350,0,0,0,-1).

FORMULA

G.f.: -(x^2-x-1)*(x^4+26*x^2+1) / (x^8-1350*x^4+1). - Colin Barker, Dec 07 2013

a(n) = 1350*a(n-4) - a(n-8) for n>7. - Vincenzo Librandi, Jan 19 2014

MATHEMATICA

Denominator[Convergents[Sqrt[674], 30]] (* Vincenzo Librandi, Jan 19 2014 *)

PROG

(MAGMA) I:=[1, 1, 25, 26, 1325, 1351, 33749, 35100]; [n le 8 select I[n] else 1350*Self(n-4)-Self(n-8): n in [1..40]]; // Vincenzo Librandi, Jan 19 2014

CROSSREFS

Cf. A042296, A040648.

Sequence in context: A042294 A041311 A042296 * A042298 A157091 A070662

Adjacent sequences:  A042294 A042295 A042296 * A042298 A042299 A042300

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Dec 07 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 May 9 19:47 EDT 2021. Contains 343746 sequences. (Running on oeis4.)