a(0) = 1, a(1) = 9, a(n) = 6*a(n-1) - a(n-2) - 4.

Terms

a(0) =1a(1) =9a(2) =49a(3) =281a(4) =1633a(5) =9513a(6) =55441a(7) =323129a(8) =1883329a(9) =10976841a(10) =63977713a(11) =372889433a(12) =2173358881a(13) =12667263849a(14) =73830224209a(15) =430314081401