A042233 Denominators of continued fraction convergents to sqrt(642).

1, 2, 3, 74, 77, 228, 11477, 23182, 34659, 854998, 889657, 2634312, 132605257, 267844826, 400450083, 9878646818, 10279096901, 30436840620, 1532121127901, 3094679096422, 4626800224323, 114137884480174, 118764684704497, 351667253889168, 17702127379162897

Offset

0,2

Links

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

Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,11554,0,0,0,0,0,-1).

Formula

G.f.: -(x^10 - 2*x^9 + 3*x^8 - 74*x^7 + 77*x^6 - 228*x^5 - 77*x^4 - 74*x^3 - 3*x^2 - 2*x - 1) / (x^12 - 11554*x^6 + 1). - Colin Barker, Dec 05 2013

Mathematica

Denominator[Convergents[Sqrt[642], 30]] (* Vincenzo Librandi, Jan 17 2014 *)

Crossrefs

Cf. A042232, A040616.

Sequence in context: A140546 A234237 A276197 * A176290 A371143 A370988

Adjacent sequences: A042230 A042231 A042232 * A042234 A042235 A042236

Keyword

nonn,frac,easy

Author

N. J. A. Sloane

Extensions

More terms from Colin Barker, Dec 05 2013

Status

approved