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 A338390 #8 Oct 24 2020 04:03:27
%S A338390 36,161,364,659,722,771,896,911,981,987,1241,1359,1486,1575,1822,2042,
%T A338390 2090,2435,2537,2582,2733,2870,2873,2967,2983,3012,3101,3108,3198,
%U A338390 3222,3278,3419,3465,3544,3668,3855,3860,3934,4024,4092,4188,4426,4437,4494,4511,4522
%N A338390 Numbers k such that there are exactly three biquadratefree powerful numbers (A338325) between k^2 and (k+1)^2.
%C A338390 Positions of 3's in A338326.
%C A338390 The asymptotic density of this sequence is 0.008234579... (Dehkordi, 1998).
%H A338390 Amiram Eldar, <a href="/A338390/b338390.txt">Table of n, a(n) for n = 1..6500</a>
%H A338390 Massoud H. Dehkordi, <a href="https://hdl.handle.net/2134/12177">Asymptotic formulae for some arithmetic functions in number theory</a>, Ph.D. thesis, Loughborough University, 1998.
%e A338390 36 is a term since there are exactly three biquadratefree powerful numbers, 1323 = 3^3 * 7^2, 1331 = 11^3 and 1352 = 2^3 * 13^2, between 36^2 = 1296 and (36+1)^2 = 1369.
%t A338390 bqfpowQ[n_] := AllTrue[FactorInteger[n][[;; , 2]], MemberQ[{2, 3}, #] &]; Select[Range[1000], Count[Range[#^2 + 1, (# + 1)^2 - 1], _?bqfpowQ] == 3 &]
%Y A338390 Cf. A336178, A338325, A338326, A338327, A338387, A338388, A338389, A338391, A338392.
%K A338390 nonn
%O A338390 1,1
%A A338390 _Amiram Eldar_, Oct 23 2020