1 = 12
1 + 2 + 1 = 22
1 + 2 + 3 + 2 + 1 = 32
1 + 2 + 3 + 4 + 3 + 2 + 1 = 42
1 + 2 + 3 + 4 + 5 + 4 + 3 + 2 + 1 = 52
1 + 2 + 3 + 4 + 5 + 6 + 5 + 4 + 3 + 2 + 1 = 62
1 + 2 + 3 + 4 + 5 + 6 + 7 + 6 + 5 + 4 + 3 + 2 + 1 = 72
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8
+ 7 + 6 + 5 + 4 + 3 + 2 + 1 = 82
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 +
9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1 = 92
|