A042193 Denominators of continued fraction convergents to sqrt(621).

1, 1, 12, 25, 287, 312, 15263, 15575, 186588, 388751, 4462849, 4851600, 237339649, 242191249, 2901443388, 6045078025, 69397301663, 75442379688, 3690631526687, 3766073906375, 45117444496812, 94000962899999, 1079128036396801, 1173128999296800

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, 0, 0, 15550, 0, 0, 0, 0, 0, -1).

Formula

G.f.: -(x^10 - x^9 + 12*x^8 - 25*x^7 + 287*x^6 - 312*x^5 - 287*x^4 - 25*x^3 - 12*x^2 - x - 1) / ((x^4 - 25*x^2 + 1)*(x^8 + 25*x^6 + 624*x^4 + 25*x^2 + 1)). - Colin Barker, Dec 03 2013

Mathematica

Denominator[Convergents[Sqrt[621], 30]] (* Vincenzo Librandi, Jan 16 2014 *)

Crossrefs

Cf. A042192, A040596.

Sequence in context: A195116 A041284 A171069 * A041286 A025138 A075689

Adjacent sequences: A042190 A042191 A042192 * A042194 A042195 A042196

Keyword

nonn,frac,easy

Author

N. J. A. Sloane

Extensions

More terms from Colin Barker, Dec 03 2013

Status

approved