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

Terms

a(0) =-2a(1) =-1a(2) =0a(3) =1a(4) =7a(5) =12a(6) =31a(7) =51a(8) =106a(9) =173a(10) =327a(11) =532a(12) =955a(13) =1551a(14) =2698a(15) =4377a(16) =7459a(17) =12092a(18) =20319a(19) =32923a(20) =54778a(21) =88725a(22) =146575a(23) =237348a(24) =390067a(25) =631511a(26) =1033866a(27) =1673569a(28) =2732011a(29) =4421964