OFFSET
1,1
COMMENTS
The "central term" is the term appearing at 1/2 the length of the period of the continued fraction, not the term succeeding that term. For instance, the periodic part of the continued fraction of sqrt(4139) is {2, 1, 63, 1, 2, 128}. - Harvey P. Dale, Sep 07 2012
MATHEMATICA
ct63Q[n_]:=Module[{sqrt=Sqrt[n], cf, len}, cf=If[IntegerQ[sqrt], {1}, ContinuedFraction[sqrt][[2]]]; len=Length[cf]; EvenQ[len] && cf[[len/2]]==63]; Select[ Range[17000], ct63Q] (* Harvey P. Dale, Sep 07 2012 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved