a(n) = least positive integer > a(n-1) and not (a(i)+a(j))^2 - a(k)^2 for 1<=i<=j<=k<=n.

Terms

a(0) =1a(1) =2a(2) =4a(3) =6a(4) =7a(5) =8a(6) =10a(7) =11a(8) =14a(9) =16a(10) =18a(11) =19a(12) =22a(13) =24a(14) =25a(15) =26a(16) =27a(17) =30a(18) =31a(19) =34a(20) =35a(21) =38a(22) =40a(23) =41a(24) =42a(25) =43a(26) =46a(27) =47a(28) =50a(29) =52