### Prime Numbers

A prime number is a whole number greater than 1 that has no positive divisors other than itself and 1
A whole number greater than 1 that is not prime is called a composite number.
A simple (but slow) method for determining prime numbers is called "trial division"
This consists of testing whether "n" is a multiple of any integer between 2 and SQRT(n)

`Public Function PrimeNumbers(ByVal iMaxNumbers As Integer) As Variant    Dim myarray As Variant    Dim iprimecount As Integer    Dim number As Long    Dim divisor As Long    Dim maxdivisor As Long    Dim isprime As Boolean    ReDim myarray(1 to MaxNumber, 1 to 2)    iprimecount = 1    For number = 1 to iMaxNumber       Select Case number          Case Is < 2             isprime = False         Case Is = 2             isprime = True             myarray(iprimecount,1) = number             iprimecount = iprimecount + 1         Case Is > 2             isprime = True             If number Mod 2 = 0 Then                 isprime = False             Else                   maxdivisor = CLnd(Sqr(number))                    divisor = 3                    Do While (divisor <= maxdivisor)                        If (number Mod divisor = 0) Then                           isprime = False                           Exit Do                        End If                        divisor = divisor + 1                    Loop                End If                If (isprime = True) Then                    myarray(ipriecount, 1) = number                    iprimecount = iprimecount + 1                End If           End Select           If (isprime = True) Then               'MsgBox number & " is prime"          Else               'MsgBox number & " is not prime"         End If      Next number    PrimeNumbers = myarray End Function `