Duplicate of A002729.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =6a(5) =6a(6) =13a(7) =10a(8) =24a(9) =22a(10) =45a(11) =30a(12) =158a(13) =74a(14) =245a(15) =368a(16) =693a(17) =522a(18) =2637a(19) =1610a(20) =7386