3,6,12,24,.....

We note that the constance term is r= 2

a1= 3

a2= 3*r = 3*2 = 6

A3= 3*r^2 = 3*2^2 = 3*4 = 12

a4 = 3*r^3 = 3*8 = 24

.....

a9= 3*r^8 = 3*2^8 = 3*256 = 768

an = 3^r^(n-1)= 3*2^(n-1)

3,6,12,24,.....

We note that the constance term is r= 2

a1= 3

a2= 3*r = 3*2 = 6

A3= 3*r^2 = 3*2^2 = 3*4 = 12

a4 = 3*r^3 = 3*8 = 24

.....

a9= 3*r^8 = 3*2^8 = 3*256 = 768

an = 3^r^(n-1)= 3*2^(n-1)