a(n) = least positive integer > a(n-1) and not a(i)+a(j)+a(k) for 1<=i<j<k<=n.

Terms

a(0) =1a(1) =2a(2) =4a(3) =5a(4) =6a(5) =14a(6) =16a(7) =18a(8) =30a(9) =42a(10) =43a(11) =44a(12) =56a(13) =69a(14) =70a(15) =82a(16) =83a(17) =95a(18) =96a(19) =108a(20) =109a(21) =121a(22) =122a(23) =134a(24) =135a(25) =147a(26) =148a(27) =160a(28) =161a(29) =173