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) = 2, a(3) = 3.

Terms

a(0) =-1a(1) =-1a(2) =2a(3) =3a(4) =13a(5) =20a(6) =49a(7) =77a(8) =158a(9) =251a(10) =473a(11) =756a(12) =1357a(13) =2177a(14) =3790a(15) =6095a(16) =10397a(17) =16748a(18) =28169a(19) =45429a(20) =75646a(21) =122099a(22) =201841a(23) =325988a(24) =536021a(25) =866105a(26) =1418510a(27) =2292807a(28) =3744085a(29) =6053276