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

Terms

a(0) =-2a(1) =0a(2) =0a(3) =1a(4) =5a(5) =8a(6) =21a(7) =33a(8) =70a(9) =111a(10) =213a(11) =340a(12) =617a(13) =989a(14) =1734a(15) =2787a(16) =4777a(17) =7692a(18) =12981a(19) =20929a(20) =34934a(21) =56375a(22) =93357a(23) =150756a(24) =248209a(25) =401013a(26) =657414a(27) =1062523a(28) =1736321a(29) =2807036