This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A031868 #12 Aug 14 2025 02:15:17
%S A031868 11806,11839,13729,16246,17461,17761,18061,18529,20409,21241,21718,
%T A031868 21871,22171,22177,22549,22699,23929,24151,24369,24829,25078,25429,
%U A031868 26116,27529,28102,28603,28807,28813,29383,29449,29476,29649,29661,30669,30796,30961
%N A031868 Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 100 ones.
%H A031868 Amiram Eldar, <a href="/A031868/b031868.txt">Table of n, a(n) for n = 1..10000</a>
%t A031868 q[k_] := Module[{c = ContinuedFraction[Sqrt[k]]}, Length[c] == 2 && Count[c[[2]], 1] == 100]; Select[Range[30000], q] (* _Amiram Eldar_, Aug 14 2025 *)
%K A031868 nonn
%O A031868 1,1
%A A031868 _David W. Wilson_