OFFSET
1,1
MATHEMATICA
cf31Q[n_]:=Module[{s=Sqrt[n], cf, len}, cf=If[IntegerQ[s], {1, 1}, ContinuedFraction[ s][[2]]]; len=Length[cf]; OddQ[len]&&cf[[(len+1)/2]] == 31]; Select[Range[250000], cf31Q] (* Harvey P. Dale, Jun 01 2018 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Corrected and extended by Harvey P. Dale, Jun 01 2018
STATUS
approved