The nth term of an Arithmetic sequence is found as follows:
[tex]a_n=a_1+(n\text{ - 1)d}[/tex]where a1 is the first term, and d is the common difference. In this case:
a1 = 11
d = 111 - 11 = 100
Then, the third, fourth and fifth terms of the sequence are:
[tex]\begin{gathered} a_3=11+(3\text{ - 1)100 = 211} \\ a_4=11+(4\text{ - 1)100 = 311} \\ a_5=11+(5\text{ - 1)100 = 411} \end{gathered}[/tex]The sequence is 11, 111, 211, 311, 411