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) = -1, a(3) = 2.

Terms

a(0) =1a(1) =-1a(2) =-1a(3) =2a(4) =-1a(5) =9a(6) =4a(7) =29a(8) =25a(9) =86a(10) =95a(11) =245a(12) =308a(13) =681a(14) =925a(15) =1862a(16) =2659a(17) =5033a(18) =7436a(19) =13493a(20) =20417a(21) =35958a(22) =55351a(23) =95405a(24) =148708a(25) =252305a(26) =396917a(27) =665606a(28) =1054331a(29) =1752705