[1, 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 15, 16, 17, 18, 19, 20, 22, 23, 24, 25, 27, 29, 30, 31, 32, 33, 34, 36, 37, 38, 40, 41, 43, 44, 45, 46, 47, 48, 50, 51, 53, 54, 55, 57, 58, 59, 60, 61, 62, 64, 66, 67, 68, 69, 71, 72, 73, 74, 75, 76, 79, 80, 81, 82, 83, 85, 86, 87, 88, 89, 90]
[7, 13, 14, 21, 26, 28, 35, 39, 42, 49, 52, 56, 63, 65, 70, 77, 78, 84]
7
13
2 * 7
3 * 7
2 * 13
2^2 * 7
5 * 7
3 * 13
2 * 3 * 7
7^2
2^2 * 13
2^3 * 7
3^2 * 7
5 * 13
2 * 5 * 7
7 * 11
2 * 3 * 13
phi(n) =72
[1, 12, 6, 6, 12, 12, 4, 3, 6, 12, 6, 12, 3, 6, 12, 12, 12, 3, 6, 12, 6, 2, 3, 6, 12, 12, 12, 4, 6, 12, 6, 6, 12, 6, 12, 12, 12, 12, 6, 12, 6, 3, 12, 6, 4, 12, 12, 12, 6, 6, 2, 6, 12, 6, 6, 12, 12, 12, 3, 6, 12, 3, 12, 3, 6, 4, 12, 12, 6, 6, 12, 2]