Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
431: | \[2^{431}-1\] | 863 × 3449 × 36238481 × 76859369 × 558062249 × 4642152737<10> × 142850312799017452169<21> × 1807482391092819529831423005040763105191863029850140579776353298087457<70> |