Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 623: | \[2^{623}-1\] | 127 × 74383430474532481<17> × 618970019642690137449562111<27> × 74716964067758844321661890925503011337830328521<47> × 79674352522894354312422878450005263712074523824062110745148651289621350880376099320960953476231<95> |