A020359 Numbers k such that the continued fraction for sqrt(k) has period 20.

151, 199, 268, 367, 393, 412, 477, 511, 524, 537, 559, 606, 622, 790, 801, 863, 972, 996, 1002, 1044, 1065, 1079, 1151, 1182, 1195, 1216, 1353, 1356, 1374, 1388, 1397, 1408, 1415, 1454, 1500, 1502, 1510, 1513, 1528, 1537, 1603, 1612, 1687, 1791, 1854, 1859

Offset

1,1

Links

Table of n, a(n) for n=1..46.

Mathematica

cf20Q[n_]:=Module[{s=Sqrt[n]}, !IntegerQ[s]&&Length[ContinuedFraction[s][[2]]]==20]; Select[Range[2000], cf20Q] (* Harvey P. Dale, Mar 13 2013 *)

Crossrefs

Sequence in context: A095745 A112796 A186459 * A185936 A050969 A247346

Adjacent sequences: A020356 A020357 A020358 * A020360 A020361 A020362

Keyword

nonn

Author

David W. Wilson

Status

approved