A042197 Denominators of continued fraction convergents to sqrt(623).

1, 1, 24, 25, 1224, 1249, 29951, 31200, 1527551, 1558751, 37378824, 38937575, 1906382424, 1945319999, 46648742401, 48594062400, 2379163737601, 2427757800001, 58217593137624, 60645350937625, 2969194438143624, 3029839789081249, 72655509587012351

Offset

0,3

Links

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

Index entries for linear recurrences with constant coefficients, signature (0,0,0,1248,0,0,0,-1).

Formula

G.f.: -(x^2-x-1)*(x^4+25*x^2+1) / (x^8-1248*x^4+1). - Colin Barker, Dec 04 2013

a(n) = 1248*a(n-4) - a(n-8) for n>7. - Vincenzo Librandi, Jan 16 2014

Mathematica

Denominator[Convergents[Sqrt[623], 30]] (* Harvey P. Dale, Jun 28 2012 *)

Prog

(Magma) I:=[1, 1, 24, 25, 1224, 1249, 29951, 31200]; [n le 8 select I[n] else 1248*Self(n-4)-Self(n-8): n in [1..30]]; // Vincenzo Librandi, Jan 16 2014

Crossrefs

Cf. A042196, A040598.

Sequence in context: A042192 A042194 A042196 * A042198 A002924 A241042

Adjacent sequences: A042194 A042195 A042196 * A042198 A042199 A042200

Keyword

nonn,cofr,frac,easy,less

Author

N. J. A. Sloane.

Extensions

More terms from Colin Barker, Dec 04 2013

Status

approved