OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..150
MATHEMATICA
cf13Q[n_]:=Module[{per=ContinuedFraction[Sqrt[n]][[2]]}, OddQ[Length[ per]]&&per[[Floor[Length[per]/2]+1]]==13]; nn=43000; With[{terms = Complement[Range[nn], Range[Floor[Sqrt[nn]]]^2]}, Select[terms, cf13Q]] (* Harvey P. Dale, Nov 23 2011 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Corrected by Harvey P. Dale, Nov 23 2011
STATUS
approved