a(n) = -a(n-1) - 3*a(n-2) with n>1, a(0)=0, a(1)=1.

Terms

a(0) =0a(1) =1a(2) =-1a(3) =-2a(4) =5a(5) =1a(6) =-16a(7) =13a(8) =35a(9) =-74a(10) =-31a(11) =253a(12) =-160a(13) =-599a(14) =1079a(15) =718a(16) =-3955a(17) =1801a(18) =10064a(19) =-15467a(20) =-14725a(21) =61126a(22) =-16951a(23) =-166427a(24) =217280a(25) =282001a(26) =-933841a(27) =87838a(28) =2713685a(29) =-2977199