Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 255: | \[{21^{255}-1\over20}\] | 5 × 211 × 463 × 9391 × 18181 × 38047 × 40841 × 342211 × 25402591 × 25505004968999551<17> × 1502097124754084594737<22> × 51233569124705721849500009982296618143<38> × 11500287881306297400572689205013166485061<41> × 346846213951614446714019035689488886491130381<45> × 83064341690084723243222862579624955608825430140451274312701165552608685728436984601948049090906312508129515442953525398241865902069270571531<140> |