A042893 - OEIS

A042893

Denominators of continued fraction convergents to sqrt(978).

1, 3, 4, 7, 11, 337, 348, 685, 1033, 3784, 235641, 710707, 946348, 1657055, 2603403, 79759145, 82362548, 162121693, 244484241, 895574416, 55770098033, 168205868515, 223975966548, 392181835063, 616157801611, 18876915883393, 19493073685004, 38369989568397

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OFFSET

0,2

LINKS

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

Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,0,0,0,236674,0,0,0,0,0,0,0,0,0,-1).

FORMULA

G.f.: -(x^18 - 3*x^17 + 4*x^16 - 7*x^15 + 11*x^14 - 337*x^13 + 348*x^12 - 685*x^11 + 1033*x^10 - 3784*x^9 - 1033*x^8 - 685*x^7 - 348*x^6 - 337*x^5 - 11*x^4 - 7*x^3 - 4*x^2 - 3*x - 1) / (x^20 - 236674*x^10 + 1). - Colin Barker, Dec 25 2013

a(n) = 236674*a(n-10) - a(n-20) for n > 19. - Vincenzo Librandi, Feb 01 2014

MATHEMATICA

Denominator[Convergents[Sqrt[978], 30]] (* Vincenzo Librandi, Feb 01 2014 *)

CROSSREFS

Cf. A042892, A040946.

Sequence in context: A291853 A041153 A041781 * A132111 A164831 A085188

Adjacent sequences: A042890 A042891 A042892 * A042894 A042895 A042896

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Colin Barker, Dec 25 2013

STATUS

approved