Base 7 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 75: | \[{7^{75}-1\over6}\] | 3 × 19 × 31 × 2551 × 2801 × 29251 × 159871 × 31280679788951<14> × 217648180992721729506406538251<30> |