Let $$a_{1}, a_{2}, a_{3}$$, … be a sequence of positive integers in arithmetic progression with ommon difference 2. Also, let $$b_{1}, b_{2}, b_{3}$$, … be a sequence of positive integers in geometric progression with common ratio 2. If $$a_{1} = b_{1} = c$$, then the number of all possible values of c, for which the equality

$$2(a_{1} + a_{2} + ... + a_{n}) = (b_{1} + b_{2} + ... + b_{n}$$

hold for some positve integer n, is _______