a(n) = a(n-1) + 3*a(n-2) -2*a(n-3) - 2*a(n-4), where a(0) = 1, a(1) = -2, a(2) = 2, a(3) = 1.

Terms

a(0) =1a(1) =-2a(2) =2a(3) =1a(4) =9a(5) =12a(6) =33a(7) =49a(8) =106a(9) =163a(10) =317a(11) =496a(12) =909a(13) =1437a(14) =2538a(15) =4039a(16) =6961a(17) =11128a(18) =18857a(19) =30241a(20) =50634a(21) =81387a(22) =135093a(23) =217504a(24) =358741a(25) =578293a(26) =949322a(27) =1531711a(28) =2505609a(29) =4045512