G = $\left \{ a^{i} | 1\leq i\leq n \right \}$
G is a group in which all the elements of the group can be written as power of one element. If this property holds then G is a cyclic group.
'a' is the generator of the group.
Ex {1,2,3,4,5,6} mod 7 is cyclic group where 3 and 5 are generators.