Question

123 question time.

Determine a pattern rule for the following sequence, algebraically.

2,3,5,9,17

Answer 1

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

`a_n=2a_(n-1)-1`