From: Near-medians that avoid the corners; a combinatorial probability approach
k - 1
∑ D
2
2.25
3
3.2457
4
4.2375
9
9.2026
49
49.1153
99
99.0864
499
499.0419
999
999.0302
1999
1999.0216
9999
9,999.0099