斯特林在vba中排名第二

Question

我在VBA中创建了一个代码，用于计算第二种数字的组合数量。但在下面的示例中，只有一半的值是正确的。

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如果n等于4，则结果应为1,7,6,1。（Wikipedia stirling numbers

我得到1,7,6.5,4.16

Sub stirlingerzahlen()
Dim n As Integer
Dim sum As Double
Dim subsum As Double
Dim k As Long
Dim j As Long
n = 4

For k = 1 To n Step 1
    For j = 0 To k Step 1
       subsum = 1 / Application.WorksheetFunction.Fact(k) * (-1) ^ (k - j) * Application.WorksheetFunction.Fact(k) / Application.WorksheetFunction.Fact(j) * j ^ n
        sum = sum + subsum
    Next
    Sheets("Tabelle2").Cells(k, 1) = sum
    sum = 0
Next
End Sub

有人能找到错误吗？

Answer 1

该公式的另一个版本似乎更容易实现：

http://home.mathematik.uni-freiburg.de/junker/ss10/DAS-SS10.pdf （第13页）

这里有更新的代码：

Sub stirlingerzahlen()
Dim n As Integer
Dim sum As Double
Dim subsum As Double
Dim k As Long
Dim j As Long
n = 4

For k = 1 To n Step 1
    For j = 0 To k
        subsum = (((-1) ^ (k - j)) * ((j ^ n) / (Application.WorksheetFunction.Fact(j) * Application.WorksheetFunction.Fact(k - j))))
        sum = sum + subsum
    Next
    Sheets("Tabelle2").Cells(k, 1) = sum
    sum = 0
Next

End Sub