Complete the series: 6, 9, 18, 45, 126, ______?

369

359

329

317

Multiply the given number by 3, After multiply subtracts 9 from the same number:

6*3=18-9= 9

9*3=27-9= 18

18*3=54-9= 45

45*3=135-9= 126

126*3=378-9= 369