Forumula : answer x 7 ( -2 per step ) + aswer/2
Step 1
0x
1x
2x
3x
4x
= 0
Step 2
5x
= 120
Step 3
6x
= 720
Step 4
7x
= 2520
Step 5
8x
= 6720
Step 6
9x
= 15120