Or we may put the factors this way:--

_n_ = 2 = (11)

_n_ = 6 = 111 x 1,001

_n_ = 10 = 11,111 x 100,001

_n_ = 14 = 1,111,111 x 10,000,001

_n_ = 18 = 111,111,111 x 1,000,000,001

In the above two tables _n_ is of the form 4_m_ + 2. When _n_ is of the

form 4_m_ the factors may be written down as follows:--

_n_= 4 = (11) x (101)

_n_ = 8 = (11) x (101) x 10,001

_n_ = 12 = (11) x (101) x 100,010,001

_n_ = 16 = (11) x (101) x 1,000,100,010,001.

When _n_ = 2, we have the prime number 11; when _n_ = 3, the factors are

3 . 37; when _n_ = 6, they are 11 . 3 . 37 . 7. 13; when _n_ = 9, they

are 3^2 . 37 . 333,667. Therefore we know that factors of _n_ = 18 are

11. 3^2 . 37 . 7 . 13 . 333,667, while the remaining factor is composite

and can be split into 19 . 52579. This will show how the working may be

simplified when _n_ is not prime.

The Canterbury Puzzles, and Other Curious Problems · 第 206 / 286 题