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 A336592 #7 Jul 28 2020 10:31:32 %S A336592 1,2,3,4,5,6,7,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,25,26,28, %T A336592 29,30,31,32,33,34,35,36,37,38,39,41,42,43,44,45,46,47,48,49,50,51,52, %U A336592 53,55,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,73,74,75 %N A336592 Numbers k such that k/A008835(k) is cubefree, where A008835(k) is the largest 4th power dividing k. %C A336592 Numbers such that none of the exponents in their prime factorization is of the form 4*m + 3. %C A336592 Cohen (1963) proved that for a given number k > 2 the asymptotic density of numbers whose exponents in their prime factorization are not of the forms k*m - 1 is zeta(k)/zeta(k-1). In this sequence k = 4, and therefore its asymptotic density is zeta(4)/zeta(3) = Pi^4/(90*zeta(3)) = 0.9003926776... %H A336592 Amiram Eldar, <a href="/A336592/b336592.txt">Table of n, a(n) for n = 1..10000</a> %H A336592 Eckford Cohen, <a href="https://eudml.org/doc/140760">Arithmetical Notes, XIII. A Sequal to Note IV</a>, Elemente der Mathematik, Vol. 18 (1963), pp. 8-11. %e A336592 6 is a term since 6 = 2^1 * 3^1 and 1 is not of the form 4*m + 3. %e A336592 8 is not a term since 8 = 2^3 and 3 is of the form 4*m + 3. %t A336592 Select[Range[100], Max[Mod[FactorInteger[#][[;; , 2]], 4]] < 3 &] %Y A336592 Cf. A002117, A004709, A008835, A013662. %K A336592 nonn %O A336592 1,2 %A A336592 _Amiram Eldar_, Jul 26 2020