Duplicate of A048739.

Terms

a(0) =1a(1) =3a(2) =8a(3) =20a(4) =49a(5) =119a(6) =288a(7) =696a(8) =1681a(9) =4059a(10) =9800a(11) =23660a(12) =57121a(13) =137903a(14) =332928