在1-7这7个数字中任意选4个组合 列出所有组合的可能性 希望在excel里列出 需要如何操作？

按下ALT+F11,插入-模块,复制下列代码.按F5运行.结果显示在A1:A840
总共有840种排列.(P(4,7)),离开高中好多年,不知对不对

*************
排列
Sub aaa()
Range("a1").Select
For a = 1 To 7
For b = 1 To 7
For c = 1 To 7
For d = 1 To 7
Do While a <> b And a <> c And a <> d And b <> c And b <> d And c <> d
Sum = a & b & c & d
ActiveCell.Value = Sum
ActiveCell.Offset(1, 0).Select
Exit Do
Loop
Next
Next
Next
Next
End Sub

************
组合

Sub aaa()
Range("a1").Select
For a = 1 To 7
For b = 1 To 7
For c = 1 To 7
For d = 1 To 7
Do While a < b And a < c And a < d And b < c And b < d And c < d
Sum = a & b & c & d
ActiveCell.Value = Sum
ActiveCell.Offset(1, 0).Select
Exit Do
Loop
Next
Next
Next
Next
End Sub

COMBIN(number,number_chosen)

COMBIN(7,4)=