A031840 Period of continued fraction for sqrt(n) contains exactly 72 ones.

4999, 5119, 5779, 7324, 7681, 8926, 9241, 9286, 10501, 10969, 11566, 11701, 12169, 12268, 12637, 13201, 13561, 14169, 14347, 14929, 14932, 15493, 15676, 15681, 15817, 16438, 16657, 17137, 17229, 17317, 17959, 18022, 18406, 18969, 18973, 19281, 19657

Offset

1,1

Links

Table of n, a(n) for n=1..37.

Mathematica

cf72Q[n_]:=Module[{s=Sqrt[n], cf}, If[IntegerQ[s], cf={0}, cf= ContinuedFraction[ s] [[2]]]; Count[cf, 1]==72]; Select[Range[ 20000], cf72Q] (* Harvey P. Dale, Jan 14 2015 *)

Crossrefs

Sequence in context: A248486 A070001 A145540 * A059667 A106767 A157367

Adjacent sequences: A031837 A031838 A031839 * A031841 A031842 A031843

Keyword

nonn

Author

David W. Wilson

Status

approved