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A013650 Period of continued fraction for sqrt(n) contains exactly three 1's. 1
7, 32, 75, 88, 136, 215, 279, 280, 312, 403, 427, 560, 711, 736, 851, 880, 923, 1007, 1067, 1272, 1311, 1363, 1431, 1495, 1736, 1855, 1887, 1955, 1976, 1995, 2128, 2159, 2184, 2272, 2511, 2567, 2640, 2728, 2880, 3055, 3211, 3560, 3751, 3811, 3927, 3984 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

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

LINKS

Table of n, a(n) for n=1..46.

MATHEMATICA

Select[ Range@ 1900, !IntegerQ[ Sqrt@ #] && Count[ ContinuedFraction[ Sqrt@ #][[2]], 1] == 3 &] (* Robert G. Wilson v, Jul 03 2011 *)

CROSSREFS

Sequence in context: A153716 A153715 A060123 * A013656 A067982 A126562

Adjacent sequences:  A013647 A013648 A013649 * A013651 A013652 A013653

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified February 18 00:19 EST 2019. Contains 320237 sequences. (Running on oeis4.)