Function FACTLN(N)
    Dim A(100)
    For I = 1 To 100
        A(I) = -1#
    Next I
    If N < 0 Then
        Print "negative factorial"
        Exit Function
    End If
    If N <= 99 Then
        If A(N + 1) < 0# Then A(N + 1) = GAMMLN(N + 1#)
        FACTLN = A(N + 1)
    Else
        FACTLN = GAMMLN(N + 1#)
    End If
End Function