a(0)=0, a(1)=1, a(2)=2 and a(n) = a(n-1) - 2a(n-2) + a(n-3).

Terms

a(0) =0a(1) =1a(2) =2a(3) =0a(4) =-3a(5) =-1a(6) =5a(7) =4a(8) =-7a(9) =-10a(10) =8a(11) =21a(12) =-5a(13) =-39a(14) =-8a(15) =65a(16) =42a(17) =-96a(18) =-115a(19) =119a(20) =253a(21) =-100a(22) =-487a(23) =-34a(24) =840a(25) =421a(26) =-1293a(27) =-1295a(28) =1712a(29) =3009