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) =9a(6) =10a(7) =11a(8) =12a(9) =14a(10) =15a(11) =16a(12) =17a(13) =18a(14) =19a(15) =21a(16) =22a(17) =23a(18) =24a(19) =26a(20) =27a(21) =28a(22) =29a(23) =30a(24) =31a(25) =33a(26) =34a(27) =35a(28) =36a(29) =37