A000041(n)-A000010(n).

Terms

a(0) =0a(1) =1a(2) =1a(3) =3a(4) =3a(5) =9a(6) =9a(7) =18a(8) =24a(9) =38a(10) =46a(11) =73a(12) =89a(13) =129a(14) =168a(15) =223a(16) =281a(17) =379a(18) =472a(19) =619a(20) =780a(21) =992a(22) =1233a(23) =1567a(24) =1938a(25) =2424a(26) =2992a(27) =3706a(28) =4537a(29) =5596