OFFSET
1,1
MATHEMATICA
ct13Q[n_]:=Module[{s=Sqrt[n], cf}, cf=If[IntegerQ[s], {1, 1}, ContinuedFraction[ s][[2]]]; EvenQ[Length[cf]]&&cf[[(Length[cf])/2]] == 13]; Select[Range[5200], ct13Q] (* Harvey P. Dale, Sep 04 2018 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Definition edited by Harvey P. Dale, Jul 16 2022
STATUS
approved