a(0)=a(1)=a(2)=0, a(3)=1; thereafter a(n) = 4a(n-3)-5a(n-4).

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =0a(5) =0a(6) =4a(7) =-5a(8) =0a(9) =16a(10) =-40a(11) =25a(12) =64a(13) =-240a(14) =300a(15) =131a(16) =-1280a(17) =2400a(18) =-976a(19) =-5775a(20) =16000a(21) =-15904a(22) =-18220a(23) =92875a(24) =-143616a(25) =6640a(26) =462600a(27) =-1038839a(28) =744640a(29) =1817200