Length of longest chain of subgroups in S_n.

Terms

a(0) =0a(1) =1a(2) =2a(3) =4a(4) =5a(5) =6a(6) =7a(7) =10a(8) =11a(9) =12a(10) =13a(11) =15a(12) =16a(13) =17a(14) =18a(15) =22a(16) =23a(17) =24a(18) =25a(19) =27a(20) =28a(21) =29a(22) =30a(23) =33a(24) =34a(25) =35a(26) =36a(27) =38a(28) =39a(29) =40