Base 18 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 55: | \[{18^{55}-1\over17}\] | 23 × 41 × 199 × 2711 × 16127 × 51217 × 50790191 × 125500908706801<15> × 24079647987394646183428194161<29> |