Procedure.i isPrime(n)
  Protected k

  If n = 2 : ProcedureReturn #True
  ElseIf n <= 1 Or n % 2 = 0 : ProcedureReturn #False
  Else
    For k = 3 To Int(Sqr(n)) Step 2
      If n % k = 0
        ProcedureReturn #False
      EndIf
    Next
  EndIf

  ProcedureReturn #True
EndProcedure

Procedure.i isWeiferich(p)
  Protected q, p2

  If Not isPrime(p) : ProcedureReturn #False : EndIf
  q = 1
  p2 = Pow(p, 2)
  While p > 1
    q = (2*q) % p2
    p - 1
  Wend
  If q = 1
    ProcedureReturn #True
  Else
    ProcedureReturn #False
  EndIf
EndProcedure

OpenConsole()
PrintN("Wieferich primes less than 5000: ")
For i = 2 To 5000
  If isWeiferich(i)
    PrintN(Str(i))
  EndIf
Next i
Input()
CloseConsole()