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) = 0, a(3) = 1.

Terms

a(0) =-1a(1) =-1a(2) =0a(3) =1a(4) =5a(5) =10a(6) =23a(7) =41a(8) =80a(9) =137a(10) =249a(11) =418a(12) =731a(13) =1213a(14) =2072a(15) =3413a(16) =5741a(17) =9410a(18) =15663a(19) =25585a(20) =42272a(21) =68881a(22) =113201a(23) =184130a(24) =301427a(25) =489653a(26) =799272a(27) =1297117a(28) =2112773a(29) =3426274