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 A320893 #7 Oct 24 2018 09:49:50 %S A320893 1296,7776,10000,12960,18144,19440,21600,27216,28512,33696,36000, %T A320893 38416,42336,42768,44064,46656,48600,49248,50544,50625,59616,60000, %U A320893 66096,73872,75168,77760,80352,89424,95256,95904,98784,100000 %N A320893 Numbers with an even number of prime factors (counted with multiplicity) that can be factored into squarefree semiprimes (A320911) but cannot be factored into distinct semiprimes (A320892). %C A320893 A semiprime (A001358) is a product of any two not necessarily distinct primes. %t A320893 sqfsemfacs[n_]:=If[n<=1,{{}},Join@@Table[Map[Prepend[#,d]&,Select[sqfsemfacs[n/d],Min@@#>=d&]],{d,Select[Rest[Divisors[n]],And[SquareFreeQ[#],PrimeOmega[#]==2]&]}]]; %t A320893 strsemfacs[n_]:=If[n<=1,{{}},Join@@Table[Map[Prepend[#,d]&,Select[strsemfacs[n/d],Min@@#>d&]],{d,Select[Rest[Divisors[n]],PrimeOmega[#]==2&]}]]; %t A320893 Select[Range[10000],And[EvenQ[PrimeOmega[#]],strsemfacs[#]=={},sqfsemfacs[#]!={}]&] %Y A320893 Cf. A001055, A001358, A005117, A006881, A007717, A028260, A318871, A318953, A320655, A320656, A320891, A320892, A320894, A320911, A320912, A320913. %K A320893 nonn %O A320893 1,1 %A A320893 _Gus Wiseman_, Oct 23 2018