There are □ terms in the sequence 1,2,2

There are exactly 81 terms in the sequence.
Start counting with 1 (like non-computer people).
First term is [tex]1=2^0[/tex].
Second term is [tex]2=2^1[/tex].
Third term is [tex]2^2[/tex].
Fourth term is [tex]2^3[/tex].
In general the i-th term is [tex]2^{i - 1}[/tex].
Hope this helps :)