A031651 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 63.

24989, 49333, 80737, 81877, 168269, 169913, 223954, 288658, 289733, 291889, 294053, 365177, 367597, 526154, 530513, 536353, 537818, 540754, 621569, 623146, 627889, 629474, 631061, 634241, 740329, 839897, 843565, 854617, 858317, 955490, 959402, 965285, 971186

Offset

1,1

Links

Table of n, a(n) for n=1..33.

Mathematica

opct63Q[n_]:=Module[{s=Sqrt[n], cf, len}, If[IntegerQ[s], cf={}, cf= ContinuedFraction[ s][[2]]]; len=Length[cf]; OddQ[len]&&cf[[(len+1)/2]] == 63]; Select[Range[10^6], opct63Q] (* Harvey P. Dale, Oct 07 2014 *)

Crossrefs

Sequence in context: A139776 A214013 A252846 * A263815 A125268 A212726

Adjacent sequences: A031648 A031649 A031650 * A031652 A031653 A031654

Keyword

nonn

Author

David W. Wilson

Extensions

Corrected and extended by Harvey P. Dale, Oct 07 2014

Status

approved