词条 | 绝对素数 |
释义 | 绝对素数是指本身是素数,其逆序数也是素数的数。例如:10321与12301是绝对素数。 VB参考程序如下: Private Function prime(n As Long) As Integer Dim k As Integer prime = False For k = 2 To Sqr(n) If n Mod k = 0 Then Exit Function Next k prime = True End Function Private Sub Command1_Click() Dim m As Long, n As Long For m = 10001 To 99999 Step 2 n = nx(m) If prime(m) And prime(n) And m <> n Then list1.AddItem "(" & m & "," & n & ")" End If Next m End Sub Private Sub Command2_Click() list1.Clear End Sub Private Function nx(n As Long) As Long Dim p As Integer, s As String Do p = n Mod 10 s = s & p n = n / 10 Loop Until n <= 0 nx = Val(s) End Function |
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