OFFSET
1,1
MATHEMATICA
okQ[k_] := Module[{c, lc}, If[IntegerQ[Sqrt[k]], False,
c = ContinuedFraction[Sqrt[k]]; lc = Length[c[[2]]];
EvenQ[lc] && c[[2, lc/2]] == 17]];
Select[Range[10000], okQ] (* Jean-François Alcover, Jul 09 2021 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved