A031617 Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 29.

5501, 10453, 17770, 18037, 26365, 27017, 36269, 49066, 63793, 76537, 81017, 112754, 114773, 116129, 132394, 133121, 134581, 135314, 136049, 136786, 138266, 139009, 139754, 140501, 154393, 159133, 180617, 185741, 187465, 203461, 204362

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Crossrefs

Subsequence of A003814.

Programs

Mathematica

opct29Q[n_]:=Module[{cf=ContinuedFraction[Sqrt[n]][[2]],len}, len= Length[ cf]; OddQ[len]&&cf[[Floor[len/2]]]==29]; Select[Range[205000], !IntegerQ[Sqrt[#]]&&opct29Q[#]&] (* Harvey P. Dale, Dec 14 2011 *)

Extensions

Corrected by Harvey P. Dale, Dec 14 2011