OCTAGON NUMBERS

There is a logical pattern to each octagon. Find the missing number.

Last Week's Answers: + 4 + 6 - 8 - 10 + 12 + 14 - 16, x 2 - 4 x 2 - 4 x 2 - 4 x 2, :

2 x 4 + 6 : 2 x 4 + 6 : 2, - 18 x 2 - 36 x 3 - 72 x 4 - 144, (3x2), (5 x 3), (7 x 4), (9 x 5), (11 x 6), (13 x 7), (15 x 8 ), (17 x 9)