







TESSERACT Сэтгvvлд орох материалууд . 2007 2 5 In fact it is easy to demonstrate the following theorems Theorem 1 If 2k 1 is a prime number then 2k 1 2k 1 is a perfect number and every even known perfect number has this form Proof Suppose first that p = 2k 1 is a prime number and set n = 2k 1 2k 1 To show n








































