Base 18 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 52: | \[{18^{52}-1\over17}\] | 52 × 132 × 19 × 53 × 79 × 131 × 521 × 2081 × 21997 × 4020180841 × 5601346141<10> × 29759719289<11> × 15715445027621<14> |