%I #10 Dec 04 2019 09:25:12
%S 0,1,2,3,4,5,6,7,8,9,10,11,13,14,15,17,18,19,22,23,26,33,34,38,46,51,
%T 58,62,82
%N Numbers which are not the sum of two squarefree semiprimes.
%C Is this a finite sequence?
%C Most probably yes. Since almost all semiprimes are squarefree, this is essentially the same as A072966. The graph of A072931 would not change qualitatively if only squarefree semiprimes were considered. - _M. F. Hasler_, Dec 03 2019
%e a(10) = 11 since there is no way to represent 11 as a sum of two squarefree semiprimes. 12 is not a term since 12 = 6 + 6.
%Y Cf. A006881, A072966.
%K nonn
%O 1,3
%A _Lior Manor_, Nov 14 2019