I have a question to ask here.There is a formula to calculate a certain ID num but i don't how to do it? any guidance?

Example.

8 7 6 5 4 3 2 1

^ ^ V V ^ ^ V ^

8=^

7=^

6=V

5=V

4=^

3=^

2=V

1=^

Easy for you to see.

if ^ = no value

if V = value.

with all the symbol of V= it shows ID num 50 all above.

how to get it?i heard by using power of 2 to get the id num.

i can't get it anyway. pls direct me to get a id num of 55.

thanks.. quite urgent!