A031534 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 36.

1298, 1318, 1346, 1358, 1362, 1366, 1382, 1394, 1398, 1438, 1442, 2919, 2949, 2964, 2973, 2991, 3057, 3063, 3081, 3093, 3102, 3117, 3153, 3171, 3174, 3189, 3207, 3237, 3246, 5188, 5204, 5212, 5228, 5244, 5252, 5260, 5276, 5284, 5300, 5308, 5324, 5340

Offset

1,1

Links

Table of n, a(n) for n=1..42.

Mathematica

cf36Q[n_]:=Module[{s=Sqrt[n], cf, len}, cf=If[IntegerQ[s], {1}, ContinuedFraction[ s][[2]]]; len=Length[cf]; EvenQ[len]&&cf[[len/2]] == 36]; Select[ Range[6000], cf36Q] (* Harvey P. Dale, Aug 23 2019 *)

Crossrefs

Sequence in context: A256834 A031750 A345956 * A252468 A135125 A204945

Adjacent sequences: A031531 A031532 A031533 * A031535 A031536 A031537

Keyword

nonn

Author

David W. Wilson

Status

approved