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!)
A041477 Denominators of continued fraction convergents to sqrt(254). 2
1, 1, 15, 16, 495, 511, 7649, 8160, 252449, 260609, 3900975, 4161584, 128748495, 132910079, 1989489601, 2122399680, 65661480001, 67783879681, 1014635795535, 1082419675216, 33487226052015, 34569645727231, 517462266233249, 552031911960480, 17078419625047649 (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 (0,0,0,510,0,0,0,-1).

FORMULA

G.f.: -(x^2-x-1)*(x^4+16*x^2+1) / (x^8-510*x^4+1). - Colin Barker, Nov 18 2013

a(n) = 510*a(n-4) - a(n-8) for n>7. - Vincenzo Librandi, Dec 18 2013

MATHEMATICA

Denominator[Convergents[Sqrt[254], 30]] (* Vincenzo Librandi, Dec 18 2013 *)

PROG

(MAGMA) I:=[1, 1, 15, 16, 495, 511, 7649, 8160]; [n le 8 select I[n] else 510*Self(n-4)-Self(n-8): n in [1..40]]; // Vincenzo Librandi, Dec 18 2013

CROSSREFS

Cf. A041476, A040238.

Sequence in context: A033051 A041111 A041476 * A041478 A042099 A156530

Adjacent sequences:  A041474 A041475 A041476 * A041478 A041479 A041480

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 October 31 12:59 EDT 2020. Contains 338101 sequences. (Running on oeis4.)