A041425 Denominators of continued fraction convergents to sqrt(228).

1, 10, 301, 3020, 90901, 912030, 27451801, 275430040, 8290353001, 83178960050, 2503659154501, 25119770505060, 756096774306301, 7586087513568070, 228338722181348401, 2290973309327052080, 68957538001992910801, 691866353329256160090, 20824948137879677713501

Offset

0,2

Links

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

Index entries for linear recurrences with constant coefficients, signature (0,302,0,-1).

Formula

G.f.: -(x^2-10*x-1) / (x^4-302*x^2+1). - Colin Barker, Nov 17 2013

a(n) = 302*a(n-2) - a(n-4). - Vincenzo Librandi, Dec 17 2013

Mathematica

Denominator[Convergents[Sqrt[228], 30]] (* Vincenzo Librandi, Dec 17 2013 *)

Prog

(Magma) I:=[1, 10, 301, 3020]; [n le 4 select I[n] else 302*Self(n-2)-Self(n-4): n in [1..100]]; // Vincenzo Librandi, Dec 17 2013

Crossrefs

Cf. A041424, A040212.

Sequence in context: A293963 A152165 A228188 * A217505 A222972 A119297

Adjacent sequences: A041422 A041423 A041424 * A041426 A041427 A041428

Keyword

nonn,frac,easy

Author

N. J. A. Sloane.

Extensions

More terms from Colin Barker, Nov 17 2013

Status

approved