Minimal span of set of n elements with no 6-term arithmetic progression.

Terms

a(0) =6a(1) =7a(2) =8a(3) =9a(4) =11a(5) =12a(6) =13a(7) =14a(8) =16a(9) =17a(10) =18a(11) =19a(12) =21a(13) =22a(14) =23a(15) =24a(16) =25a(17) =28a(18) =31a(19) =32a(20) =34a(21) =35a(22) =36a(23) =38a(24) =39a(25) =40a(26) =43a(27) =44a(28) =45a(29) =47