login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A042897 Denominators of continued fraction convergents to sqrt(980). 2
1, 3, 10, 13, 23, 59, 82, 141, 505, 1656, 103177, 311187, 1036738, 1347925, 2384663, 6117251, 8501914, 14619165, 52359409, 171697392, 10697597713, 32264490531, 107491069306, 139755559837, 247246629143, 634248818123, 881495447266, 1515744265389, 5428728243433 (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, 0, 0, 0, 0, 103682, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1).

FORMULA

G.f.: -(x^18 -3*x^17 +10*x^16 -13*x^15 +23*x^14 -59*x^13 +82*x^12 -141*x^11 +505*x^10 -1656*x^9 -505*x^8 -141*x^7 -82*x^6 -59*x^5 -23*x^4 -13*x^3 -10*x^2 -3*x -1) / ((x^10 -322*x^5 +1)*(x^10 +322*x^5 +1)). - Colin Barker, Dec 25 2013

a(n) = 103682*a(n-10) - a(n-20) for n>19. - Vincenzo Librandi, Feb 01 2014

MATHEMATICA

Denominator[Convergents[Sqrt[980], 30]] (* Harvey P. Dale, Jul 23 2012 *)

CROSSREFS

Cf. A042896, A040948.

Sequence in context: A235089 A022122 A042479 * A041169 A068361 A285181

Adjacent sequences:  A042894 A042895 A042896 * A042898 A042899 A042900

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Dec 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 March 21 21:34 EDT 2019. Contains 321382 sequences. (Running on oeis4.)