A020406 Numbers k such that the continued fraction for sqrt(k) has period 67.

1381, 1789, 2521, 3754, 3994, 5953, 6389, 7349, 7765, 7801, 8297, 8842, 9274, 10253, 12413, 14458, 15349, 15749, 16073, 16229, 19073, 21485, 22433, 24106, 24317, 24506, 24538, 24929, 25577, 25706, 26170, 26773, 26954, 28018, 28345, 30197, 32218, 32290

Offset: 1

Author

David W. Wilson

Keywords

• nonn
• changed

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A003285.

Programs

Mathematica

cf67Q[n_]:=Module[{s=Sqrt[n]},If[IntegerQ[s],1,Length[ ContinuedFraction[ s][[2]]]]==67]; Select[Range[33000],cf67Q] (* Harvey P. Dale, Sep 21 2018 *)