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 A330975 #11 Jan 26 2020 20:42:45 %S A330975 11,13,20,23,24,26,28,29,30,35,36,37,39,41,45,47,48,49,50,51,53,58,60, %T A330975 62,63,65,66,68,69,71,72,73,75,77,78,79,81,82,84,85,86,87,90,92,94,95, %U A330975 96,97,98,99,101,102,103,105,106,107,108,109,113,114,115,118 %N A330975 Numbers that are not the number of factorizations of n into distinct factors > 1 for any n. %C A330975 Warning: I have only confirmed the first three terms. The rest are derived from A045779. - _Gus Wiseman_, Jan 07 2020 %H A330975 R. E. Canfield, P. Erdős and C. Pomerance, <a href="http://math.dartmouth.edu/~carlp/PDF/paper39.pdf">On a Problem of Oppenheim concerning "Factorisatio Numerorum"</a>, J. Number Theory 17 (1983), 1-28. %t A330975 nn=20; %t A330975 fam[n_]:=fam[n]=If[n<=1,{{}},Join@@Table[Map[Prepend[#,d]&,Select[fam[n/d],Min@@#>=d&]],{d,Rest[Divisors[n]]}]]; %t A330975 nds=Length/@Array[Select[fam[#],UnsameQ@@#&]&,2^nn]; %t A330975 Complement[Range[nn],nds] %Y A330975 Complement of A045779. %Y A330975 The non-strict version is A330976. %Y A330975 Factorizations are A001055, with image A045782, with complement A330976. %Y A330975 Strict factorizations are A045778, with image A045779. %Y A330975 The least positive integer with n strict factorizations is A330974(n). %Y A330975 Cf. A001222, A002033, A025487, A033833, A045780, A045783, A318286, A328966, A330972, A330973, A330997. %K A330975 nonn %O A330975 1,1 %A A330975 _Gus Wiseman_, Jan 07 2020