A042701 Denominators of continued fraction convergents to sqrt(880).

1, 1, 2, 3, 176, 179, 355, 534, 31327, 31861, 63188, 95049, 5576030, 5671079, 11247109, 16918188, 992502013, 1009420201, 2001922214, 3011342415, 176659782284, 179671124699, 356330906983, 536002031682, 31444448744539, 31980450776221, 63424899520760

Offset

0,3

Links

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

Index entries for linear recurrences with constant coefficients, signature (0,0,0,178,0,0,0,-1).

Formula

G.f.: -(x^2-x-1)*(x^4+3*x^2+1) / (x^8-178*x^4+1). - Colin Barker, Dec 21 2013

a(n) = 178*a(n-4) - a(n-8) for n>7. - Vincenzo Librandi, Dec 21 2013

Mathematica

Denominator[Convergents[Sqrt[880], 30]] (* Vincenzo Librandi Dec 21 2013 *)
LinearRecurrence[{0, 0, 0, 178, 0, 0, 0, -1}, {1, 1, 2, 3, 176, 179, 355, 534}, 30] (* Harvey P. Dale, Dec 09 2018 *)

Prog

(Magma) I:=[1, 1, 2, 3, 176, 179, 355, 534]; [n le 8 select I[n] else 178*Self(n-4)-Self(n-8): n in [1..70]]; // Vincenzo Librandi, Dec 21 2013

Crossrefs

Cf. A042700, A040850.

Sequence in context: A042369 A371273 A328257 * A371232 A246488 A106715

Adjacent sequences: A042698 A042699 A042700 * A042702 A042703 A042704

Keyword

nonn,frac,easy

Author

N. J. A. Sloane.

Extensions

More terms from Colin Barker, Dec 21 2013

Status

approved