M = (n-1) × 1 + (n-2) × 2 + (n-3) × 4 + (n-4) × 8 + (N-5) × 16 + (n-6) × 32 + (N-7) × 64?

M = (n-1) × 1 + (n-2) × 2 + (n-3) × 4 + (n-4) × 8 + (N-5) × 16 + (n-6) × 32 + (N-7) × 64?

M=(N-1)×1+(N-2)×2+(N-3)×4+(N-4)×8+(N-5)×16+(N-6)×32+(N-7)×64+...（N-n-1)×2n…… ① 2M=(N-1)×2+(N-2)×4+(N-3)×8+(N-4)×16+(N-5)×32+(N-6)×64+(N-7)×128+...（N-n-1)×2(n+1)…… ② From ① to ②, we get - M = n (1-2 (n + 1)) + n * 2 (n + 1) + 1 m = n (- 1 + 2 (n + 1)) - n * 2 (n + 1) - 1 m = 127 * n-769

The reduction ratio is 3 / 5:0.2 1 / 2:4 / 3 5 / 6:2 4 / 5:2 / 3

3/5:0.2
=0.6:0.2
=3：!
1/2:4/3
=1/2÷4/3
=3:8
5/6:2
=5:12
4/5:2/3
=6:5
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Simplification ratio: 2 / 5:3 / 4 1.6:24

8 to 15