Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 102: | \[{21^{102}-1\over20}\] | 2 × 11 × 103 × 421 × 463 × 11969 × 38047 × 114089969144083169<18> × 1502097124754084594737<22> × 51233569124705721849500009982296618143<38> × 20813096623337757798888685318376525907607<41> |