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 A031411 #14 Aug 18 2021 00:15:00
%S A031411 66,86,94,98,147,177,183,201,213,222,260,268,284,292,300,316,332,340,
%T A031411 348,356,364,388,396,405,430,470,505,545,582,605,606,618,620,750,762,
%U A031411 791,826,847,889,894,917,938,973,994,1032,1043,1057,1106,1113,1141,1162
%N A031411 Numbers k such that the continued fraction for sqrt(k) has even period 2*m and the m-th term of the periodic part is 8.
%H A031411 T. D. Noe, <a href="/A031411/b031411.txt">Table of n, a(n) for n = 1..1000</a>
%t A031411 n = 1; t = {}; While[Length[t] < 50, n++; If[! IntegerQ[Sqrt[n]], c = ContinuedFraction[Sqrt[n]]; len = Length[c[[2]]]; If[EvenQ[len] && c[[2, len/2]] == 8, AppendTo[t, n]]]]; t (* _T. D. Noe_, Apr 04 2014 *)
%Y A031411 Cf. A031404-A031423.
%K A031411 nonn
%O A031411 1,1
%A A031411 _David W. Wilson_