A020445 Numbers k such that the period of the continued fraction for sqrt(k) contains exactly nine 1's.

819, 1079, 1144, 1491, 2832, 2923, 3175, 3567, 4015, 4087, 4163, 4439, 4727, 5123, 5307, 5459, 5695, 5875, 6027, 6107, 6519, 6696, 6767, 6992, 7192, 7839, 7912, 8003, 8211, 8375, 9263, 9831, 9976, 10123, 10127, 10600, 11256, 11507, 11835, 12136

Offset

1,1

Links

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

Mathematica

q[k_] := Module[{c = ContinuedFraction[Sqrt[k]]}, Length[c] == 2 && Count[c[[2]], 1] == 9]; Select[Range[13000], q] (* Amiram Eldar, Aug 09 2025 *)

Crossrefs

Sequence in context: A332181 A266059 A356414 * A356416 A143252 A200565

Adjacent sequences: A020442 A020443 A020444 * A020446 A020447 A020448

Keyword

nonn

Author

David W. Wilson

Status

approved