Simple number function recognition

The sequence of numbers is formed by starting with 5, and, for each consecutive term, adding a quantity that begins with 3 and doubles each time. The sequence is:

- the number that replaces the square;

- the number that replaces the circle.

is calculated from by taking the square of , then affixing a negative symbol in front if and only if is odd. Therefore, to get the that corresponds to , first, square 5:

Next, affix a negative symbol in front to make it , the correct answer.