F(1)=2
F(2)=4
F(n)=3*F(n-1)-2*F(n-2)
F(3)=12-4=8
F(4)=24-8=16
F(5)=48-16=32
F(6)=96-32=64
F(7)=192-64=128
F(1)=2
F(2)=4
F(n)=3*F(n-1)-2*F(n-2)
F(3)=12-4=8
F(4)=24-8=16
F(5)=48-16=32
F(6)=96-32=64
F(7)=192-64=128