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

Terms

a(0) =-1a(1) =-1a(2) =2a(3) =1a(4) =11a(5) =12a(6) =39a(7) =51a(8) =122a(9) =173a(10) =359a(11) =532a(12) =1019a(13) =1551a(14) =2826a(15) =4377a(16) =7715a(17) =12092a(18) =20831a(19) =32923a(20) =55802a(21) =88725a(22) =148623a(23) =237348a(24) =394163a(25) =631511a(26) =1042058a(27) =1673569a(28) =2748395a(29) =4421964