whats up with the creepy rabbit
anyway
we see we add 1, add 2 add 3, add4, add 8?
wait
ah,
double and minus 1
f(n)=2f(n-1)-1
and the first term is 2
hmm
it can't be put into an aritmetic sequcne because there isn't a single common differnce
so we wil have to say
f(n)=2f(n-1)-1
where f(1)=2
or in another form
[tex]a_n=2a_{n-1}-1[/tex]
