Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 307: | \[2^{307}-1\] | 14608903 × 85798519 × 23487583303<11> × 78952752017<11> × 112177476474470525577861298937835338545723093134076373561<57> |