Fibonacci sequence beginning 0, 4.

Terms

a(0) =0a(1) =4a(2) =4a(3) =8a(4) =12a(5) =20a(6) =32a(7) =52a(8) =84a(9) =136a(10) =220a(11) =356a(12) =576a(13) =932a(14) =1508a(15) =2440a(16) =3948a(17) =6388a(18) =10336a(19) =16724a(20) =27060a(21) =43784a(22) =70844a(23) =114628a(24) =185472a(25) =300100a(26) =485572a(27) =785672a(28) =1271244a(29) =2056916