Number Theory/Powers modulo 19

The following table shows the powers of integers modulo 19.

x x2 x3 x4 x5 x6 x7 x8 x9 x10 x11 x12 x13 x14 x15 x16 x17 x18
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
2 4 8 16 13 7 14 9 18 17 15 11 3 6 12 5 10 1
3 9 8 5 15 7 2 6 18 16 10 11 14 4 12 17 13 1
4 16 7 9 17 11 6 5 1 4 16 7 9 17 11 6 5 1
5 6 11 17 9 7 16 4 1 5 6 11 17 9 7 16 4 1
6 17 7 4 5 11 9 16 1 6 17 7 4 5 11 9 16 1
7 11 1 7 11 1 7 11 1 7 11 1 7 11 1 7 11 1
8 7 18 11 12 1 8 7 18 11 12 1 8 7 18 11 12 1
9 5 7 6 16 11 4 17 1 9 5 7 6 16 11 4 17 1
10 5 12 6 3 11 15 17 18 9 14 7 13 16 8 4 2 1
11 7 1 11 7 1 11 7 1 11 7 1 11 7 1 11 7 1
12 11 18 7 8 1 12 11 18 7 8 1 12 11 18 7 8 1
13 17 12 4 14 11 10 16 18 6 2 7 15 5 8 9 3 1
14 6 8 17 10 7 3 4 18 5 13 11 2 9 12 16 15 1
15 16 12 9 2 11 13 5 18 4 3 7 10 17 8 6 14 1
16 9 11 5 4 7 17 6 1 16 9 11 5 4 7 17 6 1
17 4 11 16 6 7 5 9 1 17 4 11 16 6 7 5 9 1
18 1 18 1 18 1 18 1 18 1 18 1 18 1 18 1 18 1