3 3 x 15 July 8, 2019 16 32 64 128 3 1 3 x 15 3 3 4 x 15 3 3 5 x 15 3 2 3 x 15 3 3 4 x 15 1 2 3 8 x 3 15 3 x 3 2x 15 2 3 x 3 7 15 X 3 x 3 15 12 3 x 3x 15 3x 3 =- 3x 15