n = 18 = (11) × 111,111,111 × 90,909,091
Or we may put the factors this way:—
n = 2 = (11)
n = 6 = 111 × 1,001
n = 10 = 11,111 × 100,001
n = 14 = 1,111,111 × 10,000,001
n = 18 = 111,111,111 × 1,000,000,001
In the above two tables n is of the form 4m + 2. When n is of the form 4m the factors may be written down as follows:—
n= 4 = (11) × (101)
n = 8 = (11) × (101) × 10,001