a(0)=1, a(1)=3, a(n) = 7*a(n-1) - 9*a(n-2) for n > 1.

Terms

a(0) =1a(1) =3a(2) =12a(3) =57a(4) =291a(5) =1524a(6) =8049a(7) =42627a(8) =225948a(9) =1197993a(10) =6352419a(11) =33684996a(12) =178623201a(13) =947197443a(14) =5022773292a(15) =26634636057a(16) =141237492771a(17) =748950724884