A042757 Denominators of continued fraction convergents to sqrt(909).

1, 6, 7, 20, 127, 274, 401, 2680, 161201, 969886, 1131087, 3232060, 20523447, 44278954, 64802401, 433093360, 26050404001, 156735517366, 182785921367, 522307360100, 3316630081967, 7155567524034, 10472197606001, 69988753160040, 4209797387208401

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, 0, 0, 161602, 0, 0, 0, 0, 0, 0, 0, -1).

Formula

G.f.: -(x^14 -6*x^13 +7*x^12 -20*x^11 +127*x^10 -274*x^9 +401*x^8 -2680*x^7 -401*x^6 -274*x^5 -127*x^4 -20*x^3 -7*x^2 -6*x -1) / ((x^4 -20*x^2 -1)*(x^4 +20*x^2 -1)*(x^8 +402*x^4 +1)). - Colin Barker, Dec 23 2013

Mathematica

Denominator[Convergents[Sqrt[909], 30]] (* Vincenzo Librandi, Jan 28 2014 *)

Crossrefs

Cf. A042756, A040878.

Sequence in context: A041076 A358059 A041771 * A257312 A062369 A048062

Adjacent sequences: A042754 A042755 A042756 * A042758 A042759 A042760

Keyword

nonn,frac,easy

Author

N. J. A. Sloane.

Extensions

More terms from Colin Barker, Dec 23 2013

Status

approved