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 A323521 #4 Jan 17 2019 17:17:58 %S A323521 4,6,8,9,10,12,14,15,18,20,21,22,25,26,27,28,30,32,33,34,35,38,39,42, %T A323521 44,45,46,48,49,50,51,52,55,57,58,62,63,64,65,66,68,69,70,72,74,75,76, %U A323521 77,78,80,82,85,86,87,91,92,93,94,95,96,98,99,102,105,106 %N A323521 Numbers whose number of prime factors counted with multiplicity (A001222) is not a perfect square. %t A323521 Select[Range[100],!IntegerQ[Sqrt[PrimeOmega[#]]]&] %Y A323521 Cf. A000037, A001222, A000290, A026478, A063989, A323519, A323520, A323527. %K A323521 nonn %O A323521 1,1 %A A323521 _Gus Wiseman_, Jan 17 2019