Public Function GetSix(ByVal I1 As Integer, ByVal I2 As Integer, ByVal I3 As Integer, _
                       ByVal I4 As Integer, ByVal I5 As Integer, ByVal I6 As Integer, _
                       ByRef N1 As Integer, ByRef N2 As Integer, ByRef N3 As Integer, _
                       ByRef N4 As Integer, ByRef N5 As Integer, ByRef N6 As Integer, _
                       ByRef CountLoop As Integer) As Boolean

Dim Success As Boolean = True
Dim rnd1 As New Random()
Dim target As Integer
Dim maxTries As Integer= 25000
Dim maxTriesRule5 As Integer = 15000
Dim Rule1, Rule2, Rule3, Rule4, Rule5 as Boolean
Dim Rule4N1, Rule4N2, Rule4N3, Rule5N4, Rule5N5, RuleN6 = 0

CountLoop = 0
target = I1 + I2 + I3 + I4 + I5 + I6

If target < 21 ot target > 285 then
    return false
endif

Do Until CountLoop > maxTries or Success

  ‘Loop
  CountLoop += 1  

  N1 = rnd1.next(MAX( target - 240, 1), MIN( 50, target - 15) + 1 )
  N2 = rnd1.next(MAX( target - N1 - 194, 1), MIN(50, target - 10 - N1) + 1)
  N3 = rnd1.next(MAX( target - N1 - N2 - 147, 1), MIN(50, target - 6 - N1 - N2) + 1)
  N4 = rnd1.next(MAX( target - N1 - N2 - N3 - 99, 1), MIN(50, target - 3 - N1 - N2 - N3) +1)
  N5 = rnd1.next(MAX( target - N1 - N2 - N3 - N4 - 50, 1), MIN(50, target - 1 - N1 - N2 - N3 - N4) +1)
  N6 = MAX( target - (N1 + N2 + N3 + N4 + N5), 1)

  ‘—-Rule 1, total of the inputs should equal the total of the outputs
  Rule1 = (I1 + I2 + I3 + I4 + I5 + I6) = (N1 + N2 + N3 + N4 + N5 + N6)

  ‘—-Rule 2, N1, N2, N3, N4, N5, N6 must all be different
  If Rule1 then
  Rule2 =(N1 <> N2 And N1 <> N3 And N1 <> N4 And N1 <> N5 And _
          N1 <> N6 And N2 <> N3 And N2 <> N4 And N2 <> N5 And _
          N2 <> N6 And N3 <> N4 And N3 <> N5 And N3 <> N6 And _
          N4 <> N5 And N4 <> N6 And N5 <> N6)
  Endif

  ‘—-  Rule 3, N1 - N6 must be between 1 and 50
  Rule3 = N6 > 0 and N6 <=50

  ‘—- Rule 4, any digit cannot appear in the same location on the output as on the input N1 not equal to I1, N2 not equal to I2
  if Rule1 and Rule2 and Rule3 then
     Rule4 = (N1 <> I1 and N2 <> I2 and N3 <> I3 and N4 <> I4 and N5 <> I5 and N6 <> I6
  Endif

  ‘—- Rule 5, any digit cannot appear in the list if this is possible
  if Rule1 and Rule3 and Rule3 and Rule4 and CountLoop < maxTriesRule5 then

     Rule5 =(N1 <> I2 And N1 <> I3 And N1 <> I4 And N1 <> I5 And N1 <> I6 And_
             N2 <> I1 And N2 <> I3 And N2 <> I4 And N2 <> I5 AND N2 <> I6 And_
             N3 <> I1 And N3 <> I2 And N3 <> I4 And N3 <> I5 And N3 <> I6 And_
             N4 <> I1 And N4 <> I2 And N4 <> I3 And N4 <> I5 And N4 <> I6 And_
             N5 <> I1 And N5 <> I2 And N5 <> I3 And N5 <> I4 And N5 <> I6 And_
             N6 <> I1 And N6 <> I2 And N6 <> I3 And N6 <> I4 And N6 <> I6 )
  Endif

  ‘—- test success
  If   (Rule1 and Rule2 and Rule3 and Rule4 and Rule5) then
    or (Rule1 and Rule2 and Rule3 and Rule4 and LoopCount> maxTriesRule5 )
    Success = True
  Else
    Success = False then
    If (Rule1 and Rule2 and Rule3 and Rule4) then  ‘— save good rule 4 answer
       Rule4N1 = N1
       Rule4N2 = N2
       Rule4N3 = N3
       Rule4N4 = N4
       Rule4N5 = N5
       Rule4N6 = N6
    Endif
  Endif
  If LoopCount > maxTriesRule5 and Rule4N1 <> 0 then ‘— exhausted rule 5 use rule 4 answer
       N1 = Rule4N1
       N2 = Rule4N2
       N3 = Rule4N3
       N4 = Rule4N4
       N5 = Rule4N5
       N6 = Rule4N6
       Success = True
  Endif
Loop
loop
Return Success
End Function

no edit on discussion
here is a change Rule4N1 .. N6 are of type Integer
.. Dim Rule4N1, Rule4N2, Rule4N3, Rule5N4, Rule5N5, RuleN6 As Integer = 0