A042789 Denominators of continued fraction convergents to sqrt(925).

1, 2, 5, 12, 29, 1752, 3533, 8818, 21169, 51156, 3090529, 6232214, 15554957, 37342128, 90239213, 5451694908, 10993629029, 27438952966, 65871534961, 159182022888, 9616792908241, 19392767839370, 48402328586981, 116197425013332, 280797178613645

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, 1764, 0, 0, 0, 0, 1).

Formula

G.f.: -(x^8 -2*x^7 +5*x^6 -12*x^5 +29*x^4 +12*x^3 +5*x^2 +2*x +1) / (x^10 +1764*x^5 -1). - Colin Barker, Dec 23 2013

a(n) = 1764*a(n-5) + a(n-10) for n>9. - Vincenzo Librandi, Jan 29 2014

Maple

convert(sqrt(925), confrac, 30, cvgts): denom(cvgts); # Wesley Ivan Hurt, Dec 23 2013

Mathematica

Denominator[Convergents[Sqrt[925], 30]] (* Harvey P. Dale, Oct 16 2013 *)

Prog

(Magma) I:=[1, 2, 5, 12, 29, 1752, 3533, 8818, 21169, 51156]; [n le 10 select I[n] else 1764*Self(n-5)+Self(n-10): n in [1..30]]; // Vincenzo Librandi, Jan 29 2014

Crossrefs

Cf. A042788, A040894.

Sequence in context: A333888 A228516 A101411 * A291253 A348619 A101911

Adjacent sequences: A042786 A042787 A042788 * A042790 A042791 A042792

Keyword

nonn,frac,easy

Author

N. J. A. Sloane.

Extensions

More terms from Colin Barker, Dec 23 2013

Status

approved