Number of subsets of {1..n} whose cardinality is not the sum of two distinct elements.

Terms

a(0) =1a(1) =2a(2) =4a(3) =7a(4) =13a(5) =25a(6) =47a(7) =88a(8) =166a(9) =313a(10) =589a(11) =1109a(12) =2089a(13) =3934a(14) =7408a(15) =13951a(16) =26273a(17) =49477a(18) =93175a(19) =175468a(20) =330442a(21) =622289a(22) =1171897a(23) =2206921a(24) =4156081a(25) =7826746a(26) =14739356a(27) =27757207a(28) =52272469a(29) =98439697