Duplicate of A069403.

Terms

a(0) =1a(1) =3a(2) =9a(3) =25a(4) =67a(5) =177a(6) =465a(7) =1219a(8) =3193a(9) =8361a(10) =21891a(11) =57313a(12) =150049a(13) =392835a(14) =1028457