a(n+3) = 5*a(n+2) - 2*a(n+1) - 8*a(n), a(0) = 1, a(1) = 0, a(2) = 3.

Terms

a(0) =1a(1) =0a(2) =3a(3) =7a(4) =29a(5) =107a(6) =421a(7) =1659a(8) =6597a(9) =26299a(10) =105029a(11) =419771a(12) =1678405a(13) =6712251a(14) =26846277a(15) =107379643a(16) =429507653a(17) =1718008763a(18) =6871991365a(19) =27487878075a(20) =109951337541a(21) =439805000635