a(n) = A000111(n) + A014695(n).

Terms

a(0) =2a(1) =3a(2) =3a(3) =3a(4) =6a(5) =18a(6) =63a(7) =273a(8) =1386a(9) =7938a(10) =50523a(11) =353793a(12) =2702766a(13) =22368258a(14) =199360983a(15) =1903757313a(16) =19391512146a(17) =209865342978