a(n) = 2a(n-2) + 4a(n-3), n >= 3.

Terms

a(0) =0a(1) =1a(2) =-1a(3) =1a(4) =2a(5) =-2a(6) =8a(7) =4a(8) =8a(9) =40a(10) =32a(11) =112a(12) =224a(13) =352a(14) =896a(15) =1600a(16) =3200a(17) =6784a(18) =12800a(19) =26368a(20) =52736a(21) =103936a(22) =210944a(23) =418816a(24) =837632a(25) =1681408a(26) =3350528a(27) =6713344a(28) =13426688a(29) =26828800