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!)
A041827 Denominators of continued fraction convergents to sqrt(434). 2
1, 1, 5, 6, 245, 251, 1249, 1500, 61249, 62749, 312245, 374994, 15312005, 15686999, 78060001, 93747000, 3827940001, 3921687001, 19514688005, 23436375006, 956969688245, 980406063251, 4878593941249, 5859000004500, 239238594121249, 245097594125749 (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 (0,0,0,250,0,0,0,-1).

FORMULA

G.f.: -(x^2-x-1)*(x^4+6*x^2+1) / (x^8-250*x^4+1). - Colin Barker, Nov 25 2013

a(n) = 250*a(n-4) - a(n-8) for n>7. - Vincenzo Librandi, Dec 25 2013

MATHEMATICA

Denominator[Convergents[Sqrt[434], 30]] (* Vincenzo Librandi, Dec 25 2013 *)

LinearRecurrence[{0, 0, 0, 250, 0, 0, 0, -1}, {1, 1, 5, 6, 245, 251, 1249, 1500}, 30] (* Harvey P. Dale, Apr 27 2018 *)

PROG

(MAGMA) I:=[1, 1, 5, 6, 245, 251, 1249, 1500]; [n le 8 select I[n] else 250*Self(n-4)-Self(n-8): n in [1..40]]; // Vincenzo Librandi, Dec 25 2013

CROSSREFS

Cf. A041826, A040413.

Sequence in context: A103089 A041601 A301648 * A042089 A156191 A042387

Adjacent sequences:  A041824 A041825 A041826 * A041828 A041829 A041830

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Nov 25 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 January 25 07:37 EST 2020. Contains 331241 sequences. (Running on oeis4.)