Base 8 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 91: | \[{8^{91}-1\over7}\] | 7 × 79 × 127 × 337 × 911 × 8191 × 121369 × 108749551 × 112901153 × 23140471537<11> × 4093204977277417<16> × 86977595801949844993<20> |