A031786 Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 18 ones.

244, 508, 556, 619, 631, 652, 694, 769, 772, 796, 811, 823, 844, 907, 964, 974, 1057, 1063, 1069, 1198, 1481, 1648, 1660, 1777, 1786, 1809, 1816, 1819, 1852, 1964, 1990, 2009, 2017, 2041, 2049, 2076, 2084, 2086, 2092, 2129, 2276, 2339, 2353, 2356, 2404

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..2000 from Harvey P. Dale)

Mathematica

cf18Q[n_]:=With[{s=Sqrt[n]}, If[IntegerQ[s], 0, Count[ContinuedFraction[s][[2]], 1]]==18]; Select[Range[2500], cf18Q] (* Harvey P. Dale, Jun 02 2025 *)

Crossrefs

Sequence in context: A044987 A201998 A234262 * A328206 A135409 A203349

Adjacent sequences: A031783 A031784 A031785 * A031787 A031788 A031789

Keyword

nonn

Author

David W. Wilson

Status

approved