Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 355: | \[2^{355}-1\] | 31 × 228479 × 48544121 × 212885833 × 121932688511<12> × 8223125624363292839815514592697905768406610797334099385507174111379292321<73> |