login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 56th year. In the past year we added 10000 new sequences and reached almost 9000 citations (which often say "discovered thanks to the OEIS").
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A041773 Denominators of continued fraction convergents to sqrt(407). 2
1, 5, 6, 17, 23, 132, 5303, 26647, 31950, 90547, 122497, 703032, 28243777, 141921917, 170165694, 482253305, 652418999, 3744348300, 150426350999, 755876103295, 906302454294, 2568481011883, 3474783466177, 19942398342768, 801170717176897, 4025795984227253 (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, 0, 0, 0, 0, 5326, 0, 0, 0, 0, 0, -1).

FORMULA

G.f.: -(x^10-5*x^9+6*x^8-17*x^7+23*x^6-132*x^5-23*x^4-17*x^3-6*x^2-5*x-1) / (x^12-5326*x^6+1). - Colin Barker, Nov 24 2013

a(n) = 5326*a(n-6) - a(n-12) for n>11. - Vincenzo Librandi, Dec 24 2013

MATHEMATICA

Denominator[Convergents[Sqrt[407], 40]] (* Harvey P. Dale, Jul 13 2012 *)

CoefficientList[Series[-(x^10 - 5 x^9 + 6 x^8 - 17 x^7 + 23 x^6 - 132 x^5 - 23 x^4 - 17 x^3 - 6 x^2 - 5 x - 1)/(x^12 - 5326 x^6 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 24 2013 *)

PROG

(MAGMA) I:=[1, 5, 6, 17, 23, 132, 5303, 26647, 31950, 90547, 122497, 703032]; [n le 12 select I[n] else 5326*Self(n-6)-Self(n-12): n in [1..50]]; // Vincenzo Librandi, Dec 24 2013

CROSSREFS

Cf. A041772, A040386.

Sequence in context: A035595 A099571 A041997 * A041054 A297980 A120034

Adjacent sequences:  A041770 A041771 A041772 * A041774 A041775 A041776

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

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 December 3 05:29 EST 2020. Contains 338899 sequences. (Running on oeis4.)