A031550 that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 52.

2706, 2722, 2734, 2774, 2786, 2798, 2802, 2818, 2838, 2846, 2854, 2866, 2878, 2882, 2894, 2902, 2914, 6087, 6117, 6126, 6132, 6159, 6189, 6213, 6231, 6249, 6261, 6276, 6297, 6321, 6333, 6357, 6369, 6393, 6411, 6414, 6429, 6513, 6537, 6549, 6558, 10820

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Mathematica

cfQ[n_]:=Module[{sqr=Sqrt[n], c}, If[IntegerQ[sqr], c={1}, c=ContinuedFraction[ sqr][[2]]]; EvenQ[Length[c]]&&c[[Length[c]/2]]==52]; Select[Range[11000], cfQ] (* Harvey P. Dale, Nov 28 2012 *)

Crossrefs

Sequence in context: A281838 A205605 A205436 * A083615 A205750 A205472

Adjacent sequences: A031547 A031548 A031549 * A031551 A031552 A031553

Keyword

nonn

Author

David W. Wilson

Status

approved