[ sqrt(3/2)^n ].

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =2a(6) =3a(7) =4a(8) =5a(9) =6a(10) =7a(11) =9a(12) =11a(13) =13a(14) =17a(15) =20a(16) =25a(17) =31a(18) =38a(19) =47a(20) =57a(21) =70a(22) =86a(23) =105a(24) =129a(25) =158a(26) =194a(27) =238a(28) =291a(29) =357