A042311 Denominators of continued fraction convergents to sqrt(682).

1, 8, 9, 26, 139, 304, 1659, 3622, 5281, 45870, 2390521, 19170038, 21560559, 62291156, 333016339, 728323834, 3974635509, 8677594852, 12652230361, 109895437740, 5727214992841, 45927615380468, 51654830373309, 149237276127086, 797841211008739, 1744919698144564

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,0,0,0,2395802,0,0,0,0,0,0,0,0,0,-1).

Formula

G.f.: -(x^18 -8*x^17 +9*x^16 -26*x^15 +139*x^14 -304*x^13 +1659*x^12 -3622*x^11 +5281*x^10 -45870*x^9 -5281*x^8 -3622*x^7 -1659*x^6 -304*x^5 -139*x^4 -26*x^3 -9*x^2 -8*x -1) / (x^20 -2395802*x^10 +1). - Colin Barker, Dec 07 2013

a(n) = 2395802*a(n-10) - a(n-20) for n>19. - Vincenzo Librandi, Jan 20 2014

Mathematica

Denominator[Convergents[Sqrt[682], 30]] (* Harvey P. Dale, Dec 29 2013 *)

Crossrefs

Cf. A042310, A040655.

Sequence in context: A108219 A041317 A305336 * A003997 A114090 A351959

Adjacent sequences: A042308 A042309 A042310 * A042312 A042313 A042314

Keyword

nonn,frac,easy

Author

N. J. A. Sloane

Extensions

More terms from Colin Barker, Dec 07 2013

Status

approved