a(n+1) = a(n-1) + 2 a(n-2) - a(n-4) ; a(0)=1, a(n)=0 for 0 < n < 5.

Terms

a(0) =1a(1) =0a(2) =0a(3) =0a(4) =0a(5) =-1a(6) =0a(7) =-1a(8) =-2a(9) =-1a(10) =-3a(11) =-5a(12) =-4a(13) =-9a(14) =-13a(15) =-14a(16) =-26a(17) =-36a(18) =-45a(19) =-75a(20) =-103a(21) =-139a(22) =-217a(23) =-300a(24) =-420a(25) =-631a(26) =-881a(27) =-1254a(28) =-1843a(29) =-2596