a(n) = a(n-1) + 3*a(n-2) -2*a(n-3) - 2*a(n-4), where a(0) = 1, a(1) = 3, a(2) = 4, a(3) = 5.

Terms

a(0) =1a(1) =3a(2) =4a(3) =5a(4) =9a(5) =10a(6) =19a(7) =21a(8) =40a(9) =45a(10) =85a(11) =98a(12) =183a(13) =217a(14) =400a(15) =489a(16) =889a(17) =1122a(18) =2011a(19) =2621a(20) =4632a(21) =6229a(22) =10861a(23) =15042a(24) =25903a(25) =36849a(26) =62752a(27) =91409a(28) =154161a(29) =229186