' FB 1.05.0 Win64

Sub getPrimeFactors(factors() As UInteger, n As UInteger)
  If n < 2 Then Return
  Dim factor As UInteger = 2
  Do
    If n Mod factor = 0 Then
      Redim Preserve factors(0 To UBound(factors) + 1)
      factors(UBound(factors)) = factor
      n \= factor
      If n = 1 Then Return
    Else
      factor += 1
    End If
  Loop
End Sub

Dim factors() As UInteger

For i As UInteger = 1 To 20
  Print Using "##"; i;
  Print " = ";
  If i > 1 Then
    Erase factors
    getPrimeFactors factors(), i
    For j As Integer = LBound(factors) To UBound(factors)
      Print factors(j);
      If j < UBound(factors) Then Print " x ";
    Next j
    Print
  Else
    Print i
  End If
Next i

Print
Print "Press any key to quit"
Sleep