A013647 Period of continued fraction for sqrt(n) contains no 1's.

2, 5, 6, 10, 11, 12, 17, 18, 20, 26, 27, 28, 30, 37, 38, 39, 40, 41, 42, 50, 51, 55, 56, 65, 66, 68, 72, 82, 83, 84, 87, 89, 90, 101, 102, 104, 105, 110, 122, 123, 126, 128, 130, 131, 132, 145, 146, 147, 148, 150, 152, 155, 156, 170, 171, 174, 177, 180, 182, 197, 198, 200, 203

Offset

1,1

References

Kenneth H. Rosen, Elementary Number Theory and Its Applications, Addison-Wesley, 1984, page 426 (but beware of errors!).

Links

T. D. Noe, Table of n, a(n) for n = 1..1000

Mathematica

cf1Q[n_]:=Module[{s=Sqrt[n]}, If[IntegerQ[s], False, FreeQ[ ContinuedFraction[ s][[2]], 1]]]; Select[Range[250], cf1Q] (* Harvey P. Dale, Jun 06 2021 *)

Crossrefs

Sequence in context: A307562 A109150 A004202 * A255068 A183987 A187840

Adjacent sequences: A013644 A013645 A013646 * A013648 A013649 A013650

Keyword

nonn

Author

Clark Kimberling

Status

approved