Primality Testing

Factor Trees

             324               165       36
                                        /  \
                                        6  6
                                       / \ /\
                                      2  3 2 3

61

    666 6*111  factors occur in pairs with one exception.


    16 4*4
    
    1 2 4 8 16

    c = a*b

1 16
2 8
4 4

36
1 36
2 18
3 12
4 9
6 6

54

1 54
2 27
3 18
6 9

List Comprehensions in Python