12, 15, 36,?, 480, 2415, 14508

Series pattern
12 x 1 + 3 x 1 = 15
15 x 2 + 3 x 2 = 36
36 x 3 + 3 x 3 = 117
Should come in place of ?
117 x 4 + 3 x 4 = 480
480 x 5 + 3 x 5 = 2415
2415 x 6 + 3 x 6 =14508