%I
%S 0,1,2,3,4,5,6,7,9,11,17,22,33
%N Numbers which are not the sum of two semiprimes.
%C Is this sequence finite?
%C See the graph of sequence A072931 for compelling evidence that 33 is the last term of this sequence.  _T. D. Noe_, Apr 11 2007
%e a(10) = 11 since there is no way to represent 11 as a sum of two semiprimes. 13 is not a term since 13 = 4 + 9.
%t lim = 10000;
%t s = Select[Range[lim], PrimeOmega[#] == 2 &];
%t c = Map[Total,Union[Subsets[s, {2}], Table[{s[[i]], s[[i]]}, {i, 1, Length[s]}]]];
%t Join[Complement[Range[0, lim], c], ">", lim ](* _Robert Price_, Mar 30 2019 *)
%Y Cf. A001358.
%K nonn,more
%O 1,3
%A _Lior Manor_ Aug 13 2002
