A041411 Denominators of continued fraction convergents to sqrt(220).

1, 1, 5, 6, 173, 179, 889, 1068, 30793, 31861, 158237, 190098, 5480981, 5671079, 28165297, 33836376, 975583825, 1009420201, 5013264629, 6022684830, 173648439869, 179671124699, 892332938665, 1072004063364

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

a(n) = 178*a(n-4)-a(n-8). G.f.: -(x^2-x-1)*(x^4+6*x^2+1)/(x^8-178*x^4+1). [Colin Barker, Jul 16 2012]

Mathematica

Denominator[Convergents[Sqrt[220], 30]] (* Vincenzo Librandi, Oct 25 2013 *)

Crossrefs

Cf. A041410.

Sequence in context: A266718 A041257 A337465 * A103089 A041601 A301648

Adjacent sequences: A041408 A041409 A041410 * A041412 A041413 A041414

Keyword

nonn,cofr,frac,easy

Author

N. J. A. Sloane.

Status

approved