Yeh it has nothing to do with geometric progression -my mistake

i didn't take enough time to think it over before asking

oooh yeh...i meant 16 not 18 - sorry

I really didn't get your way - Both bkarpuz and Mr.Fantastic,

if you can explain it more plzzzz

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Here is my way, i figured out 2 ways:

2,4,8,16,32,64 can be expressed as 2 raised to a certain power Then using these two basic rules, each value in the squence can be simplified:

1) Log (baseB)A = Log A /Log B

2) Log a^2 = 2Loga

example: Log (base4 )8

= __Log 8 __

Log 4

=__ Log 2^3 __

Log 2^2

__3 Log 2 __

2 Log 2

=__ 3__

2

The same applies for the rest

making the following pattern:

3/1 , 3,2 , 3/3, 3/4, 3/5, 3/6

Therefore, the nth-term is going to be 3/n

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2) The sequence is in the form of log[base 2^n] 8

By using the base rule, we can further simplify it beacome in the form of p/q log[base 2^n] 8 = log[base 2] 8 / log [base 2]2^n = log[base 2] 2^3 / log [base 2]2^n After crossing out the similar logs you are left with 3/n ---------------------------------- I have anthor part of the question if anyone is intrested