Can you find the last number in the below sequence puzzle?

16 105 636 3175 12704 38109 ?

76220
1
(1+1) * 8 = 16
(16-1) * 7 = 105
+1) * 6 = 636 (3175+1) * 4 = 12704
(12704-1) * 3 = 38109