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 A324174 #17 Dec 11 2022 19:06:37
%S A324174 2,4,8,12,16,24,30,36,48,56,64,80,90,100,120,132,144,168,182,196,224,
%T A324174 240,256,288,306,324,360,380,400,440,462,484,528,552,576,624,650,676,
%U A324174 728,756,784,840,870,900,960,992,1024,1088,1122,1156,1224,1260,1296
%N A324174 Integers k such that 2*floor(sqrt(k)) divides k.
%H A324174 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,2,-2,0,-1,1).
%F A324174 For k >= 1, a(3k-2) = 4k^2 - 2k, a(3k-1) = 4k^2 and a(3k) = 4k^2 + 4k.
%t A324174 Select[ Range[ 1000 ], Mod[ #, 2*Floor[ Sqrt[ # ]//N ] ]==0& ]
%t A324174 LinearRecurrence[{1,0,2,-2,0,-1,1},{2,4,8,12,16,24,30},70] (* _Harvey P. Dale_, Dec 11 2022 *)
%o A324174 (PARI) is(n) = n%(2*sqrtint(n)) == 0;
%Y A324174 Cf. A006446, A324175, A324176, A324177, A324178.
%K A324174 nonn
%O A324174 1,1
%A A324174 _Jinyuan Wang_, Mar 09 2019