Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 213: | \[{21^{213}-1\over20}\] | 463 × 1091413 × 11923741 × 493509073 × 22461400068241<14> × 11279356843588755387709147<26> × 6912925952086714539251625713<28> × 365925666294052289788363465921686827983831<42> × 110556144297525239244017467747224789359885811468762753179<57> × 101869264981453350052709006811951233962746630636015451046824621165526717402085424225208733181<93> |