22
222 - 1 = 3 * 23 * 89 * 683
1022 - 1 = 3 * 3 * 11 * 11 * 23 * 4093 * 8779 * 21649 * 513239
21 - 22 - 23
0 - 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9
Mathematics Encyclopedia
Hellenica World - Scientific Library
