A020443 Numbers k such that the period of the continued fraction for sqrt(k) contains exactly seven 1's.

115, 135, 247, 464, 611, 744, 767, 1064, 1479, 2079, 2200, 2291, 2360, 2875, 3096, 3283, 3367, 3800, 4187, 4255, 4408, 4672, 4720, 4995, 5151, 5375, 5568, 5611, 5983, 6235, 6431, 6643, 6816, 6840, 6895, 7335, 7367, 7600, 8151, 8208, 8507, 8755, 8843

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..300 from Harvey P. Dale)

Mathematica

pcf7Q[n_]:=Module[{sr=Sqrt[n]}, !IntegerQ[sr]&&Count[ContinuedFraction[ sr][[2]], 1]==7]; Select[Range[9000], pcf7Q] (* Harvey P. Dale, Nov 27 2012 *)

Crossrefs

Sequence in context: A105993 A036269 A036462 * A129544 A095621 A051975

Adjacent sequences: A020440 A020441 A020442 * A020444 A020445 A020446

Keyword

nonn

Author

David W. Wilson

Status

approved