The first rule is that the next number is equal to the value of the previous number multiplied by 3. Answer 3/2 8 1/2.

The second rule is that the next number equals the value of the previous number multiplied by 1/4. Answer 1/4 1/256.

The third rule is that the next number is equal to the value of the previous number multiplied by 3/2 answer 81/32 243/64 729/128.

The fourth law, (3n-2)/(n+ 1)*2, the answer