A042245 Denominators of continued fraction convergents to sqrt(648).

1, 2, 11, 68, 351, 770, 38851, 78472, 431211, 2665738, 13759901, 30185540, 1523036901, 3076259342, 16904333611, 104502261008, 539415638651, 1183333538310, 59706092554151, 120595518646612, 662683685787211, 4096697633369878, 21146171852636601

Offset

0,2

Links

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

Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,39202,0,0,0,0,0,-1).

Formula

G.f.: -(x^10 - 2*x^9 + 11*x^8 - 68*x^7 + 351*x^6 - 770*x^5 - 351*x^4 - 68*x^3 - 11*x^2 - 2*x - 1) / ((x^2 - 6*x + 1)*(x^2 + 6*x + 1)*(x^4 - 6*x^3 + 35*x^2 - 6*x + 1)*(x^4 + 6*x^3 + 35*x^2 + 6*x + 1)). - Colin Barker, Dec 05 2013

Mathematica

Denominator[Convergents[Sqrt[648], 30]] (* Vincenzo Librandi, Jan 18 2014 *)

Crossrefs

Cf. A042244, A040622.

Sequence in context: A058056 A266579 A063768 * A153298 A153393 A365135

Adjacent sequences: A042242 A042243 A042244 * A042246 A042247 A042248

Keyword

nonn,frac,easy

Author

N. J. A. Sloane

Extensions

More terms from Colin Barker, Dec 05 2013

Status

approved