Number of subsets of {1..n} containing n but not containing the sum of any two distinct elements.

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =6a(5) =9a(6) =15a(7) =24a(8) =41a(9) =60a(10) =99a(11) =149a(12) =236a(13) =355a(14) =552a(15) =817a(16) =1275a(17) =1870a(18) =2788a(19) =4167a(20) =6243a(21) =9098a(22) =13433a(23) =19718a(24) =28771a(25) =42137a(26) =60652a(27) =88603a(28) =127555a(29) =185200