A031746 - OEIS

%I #16 Jul 16 2021 02:41:54

%S 1157,4626,10407,18500,28905,41622,56651,73992,93645,115610,139887,

%T 166476,195377,226590,260115,295952,334101,374562,417335,462420,

%U 509817,559526,611547,665880,722525,781482,842751,906332,972225,1040430,1110947

%N Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 68.

%C a(n) = 1156n^2 + n for n < 71, but a(71) = 5669230. - _Charles R Greathouse IV_, Aug 04 2017

%H Charles R Greathouse IV, <a href="/A031746/b031746.txt">Table of n, a(n) for n = 1..10000</a>

%t lt68Q[n_]:=Module[{s=Sqrt[n]},If[IntegerQ[s],1,Min[ContinuedFraction[s][[2]]]==68]]; Select[Range[12*10^5],lt68Q] (* _Harvey P. Dale_, Jun 07 2018 *)

%K nonn

%O 1,1

%A _David W. Wilson_