Except for initial 0, same as A005213.

Terms

a(0) =0a(1) =0a(2) =1a(3) =1a(4) =3a(5) =2a(6) =7a(7) =6a(8) =19a(9) =16a(10) =51a(11) =45a(12) =141a(13) =126a(14) =393a(15) =357a(16) =1107a(17) =1016a(18) =3139a(19) =2907a(20) =8953