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A013647 Period of continued fraction for sqrt(n) contains no 1's. 3
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
REFERENCES
Kenneth H. Rosen, Elementary Number Theory and Its Applications, Addison-Wesley, 1984, page 426 (but beware of errors!).
LINKS
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
KEYWORD
nonn
AUTHOR
STATUS
approved

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Last modified March 28 14:13 EDT 2024. Contains 371254 sequences. (Running on oeis4.)