Duplicate of A023819.

Terms

a(0) =1a(1) =2a(2) =4a(3) =4a(4) =4a(5) =6a(6) =8a(7) =6a(8) =7a(9) =8a(10) =11a(11) =11a(12) =11a(13) =11a(14) =12a(15) =10a(16) =12a(17) =11a(18) =15a(19) =13a(20) =13a(21) =18a(22) =18a(23) =17a(24) =16a(25) =17a(26) =19a(27) =17