OFFSET
1,1
REFERENCES
Kenneth H. Rosen, Elementary Number Theory and Its Applications, Addison-Wesley, 1984, p. 426 (but beware of errors!).
MATHEMATICA
Select[ Range@ 1900, !IntegerQ[ Sqrt@ #] && Count[ ContinuedFraction[ Sqrt@ #][[2]], 1] == 3 &] (* Robert G. Wilson v, Jul 03 2011 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved