Question 1068107
<pre>
{{{-2=-2^1}}}

{{{8=2^3}}}

{{{-32=-2^5}}}

{{{128=2^7}}}

The terms of the sequence are the odd powers of 2
with alternating signs.

The general term for the sequence of exponents 1, 3, 5, 7, ...
is {{{2n-1}}}

The general term for the sequence of multipliers 1, -1, 1, -1, 1, ...
which causes alternating signs is {{{(-1)^(n+1)}}}

So the general formula is

{{{a[n]}}}{{{""=""}}}{{{(-1)^(n+1)*2^(2n-1)}}}

Edwin</pre>